Stem cell researchers at UCLA have identified a type of leukemia stem cell and uncovered the molecular and genetic mechanisms that cause a normal blood stem cells to become cancerous.
The discovery may lead to new therapies that target these leukemia stem cells, attacking the disease at its very root and killing the early cells that give rise to the mature cancer cells. The study appears in the May 22, 2008 issue of the journal Nature.
Scientists now believe stem cells are responsible for the origin of many cancers and their ability to become drug resistant and spread throughout the body. Current cancer therapies don't target cancer stem cells, only the cancer cells that are generated by them. Scientists theorize that the cancer stem cells -- a very small population when compared with mature cancer cells - lay dormant while the cancer cells are killed. Later, sometimes years later, the cancer stem cells begin to self-renew and differentiate into malignant cells, causing a recurrence of the disease.
If scientists could understand the biology of cancer stem cells and find a way to kill them, it might provide what the oncology research community never talks about -- a potential cure for certain cancers. If the cancer stem cells could be sought out and eliminated from the body, the cancer could not re-grow.
Led by Dr. Hong Wu, a professor of medical and molecular pharmacology and a scientist with the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, the UCLA team has for the first time identified and isolated the stem cells responsible for a type of leukemia known as T-cell or acute T-lymphoblastic leukemia, an aggressive and deadly cancer that , can occur in both children and adults. The team also discovered the mechanisms by which blood stem cells -- the cells that become the various cells in the blood supply -- are converted to malignant leukemia stem cells, providing potential targets for therapies to home in on and attack those stem cells.
"One of the main challenges in cancer biology is to identify cancer stem cells and define the molecular and genetic events required for transforming normal cells into cancer stem cells," said Wu, who also is a researcher at UCLA's Jonsson Comprehensive Cancer Center and senior author of the Nature study. "With this study, we've been able to do that in one type of leukemia."
In mouse models that developed T-cell leukemia, the team studied the cancerous cells and, using a sorting method that sought out certain cell surface markers, was able to identify the leukemia stem cells. Those cells were isolated and then transplanted into other mouse models to see if they developed T-cell leukemia, a sign that the team had been successful in finding the leukemia stem cells.
The team also wanted to know how blood stem cells become cancerous and studied the cells at the molecular and genetic level to uncover those mechanisms.
"We thought that multiple genetic or molecular alterations would have to occur for cancer to develop," said Wei Guo, a postdoctoral student in Wu's lab and the first author of the study. "In this case, we were able to find those alterations."
The alterations found that collaboratively contribute to leukemia stem cell formation were the deletion of the PTEN tumor suppressor gene, a chromosomal translocation involving c-myc, a gene known to result in cancer that is usually regulated and kept in line, and the activation of a cell signaling pathway called beta catenin.
Wu and her team currently are testing therapies that target the alterations they discovered, hoping to interrupt the process that causes the blood stem cells to become leukemia stem cells, thereby preventing the cancer. They're also looking for other alterations that might be at play in transforming the normal stem cells into cancerous stem cells.
Knocking Out Survival Protein Could Aid Leukemia Treatment
An effective way to fight leukemia might be to knock out a specific protein that protects cancer cells from dying, a new study shows. The findings suggest that a drug that can block this “survival protein” might on its own be an effective therapy.
Health & Medicine
Leukemia
Lymphoma
Cancer
Lung Cancer
Brain Tumor
Skin Cancer
Reference
Leukemia
Lymphoma
Tumor suppressor gene
BRCA1
But such a drug used in combination with several existing drugs might also offer an effective one-two punch against drug-resistant forms of chronic lymphocytic leukemia (CLL) and acute lymphoblastic leukemia (ALL). The two forms of cancer kill about 20,500 Americans yearly.
The survival protein is called Mcl1. It usually helps keep normal cells healthy and is involved in the development of the components of the immune system, but it can also help prolong survival of cancer cells.
Cells with an overabundance of the protein are also more resistant to anticancer drugs such as rituximab, which has revolutionized the treatment of certain chronic and acute leukemias.
“Our findings demonstrate that Mcl1 may be an effective target for drugs directed against CLL and ALL,” says principal investigator John C. Byrd, professor of internal medicine and director of the hematologic malignancies program at Ohio State's James Cancer Hospital and Solove Research Institute.
“These results give us a rationale for lowering the amount of this protein in CLL cells and suggest that this should enhance the action of rituximab and perhaps other agents as well.”
Rituximab is an antibody-based drug that targets CLL and ALL cells and causes the cells to self-destruct. “We've shown that knocking down Mcl1 can, by itself, cause CLL cells to die, and that this effect might enhance the activity of rituximab,” says first author Rehan Hussain, a postdoctoral fellow with Ohio State's Comprehensive Cancer Center.
Byrd, Hussain and their collaborators conducted this research using cancer cells from 17 CLL patients and ALL cell lines grown in the laboratory.
The investigators placed molecules called small interfering RNA (siRNA) inside the cells and found that the tiny molecules greatly reduced the amount of the survival protein, causing many of the cells to die. The effect was the same even in cells that came from patients with advanced cancer or from patients with tumors that resisted conventional treatment.
When the researchers treated cells with both siRNA and the drug rituximab, the combination killed significantly more leukemia cells than the drug alone. Overall, says Byrd, “Our data indicate that specifically targeting Mcl1 might be effective in the treatment of CLL, particularly when combined with rituximab.”
Funding from the National Cancer Institute, the Leukemia & Lymphoma Society and the D. Warren Brown Foundation supported this research. Byrd is the D. Warren Brown Professor of Leukemia Research and a Clinical Scholar of the Leukemia & Lymphoma Society. The study by researchers at the Ohio State University Comprehensive Cancer Center is published online in the journal Clinical Cancer Research.
Health & Medicine
Leukemia
Lymphoma
Cancer
Lung Cancer
Brain Tumor
Skin Cancer
Reference
Leukemia
Lymphoma
Tumor suppressor gene
BRCA1
But such a drug used in combination with several existing drugs might also offer an effective one-two punch against drug-resistant forms of chronic lymphocytic leukemia (CLL) and acute lymphoblastic leukemia (ALL). The two forms of cancer kill about 20,500 Americans yearly.
The survival protein is called Mcl1. It usually helps keep normal cells healthy and is involved in the development of the components of the immune system, but it can also help prolong survival of cancer cells.
Cells with an overabundance of the protein are also more resistant to anticancer drugs such as rituximab, which has revolutionized the treatment of certain chronic and acute leukemias.
“Our findings demonstrate that Mcl1 may be an effective target for drugs directed against CLL and ALL,” says principal investigator John C. Byrd, professor of internal medicine and director of the hematologic malignancies program at Ohio State's James Cancer Hospital and Solove Research Institute.
“These results give us a rationale for lowering the amount of this protein in CLL cells and suggest that this should enhance the action of rituximab and perhaps other agents as well.”
Rituximab is an antibody-based drug that targets CLL and ALL cells and causes the cells to self-destruct. “We've shown that knocking down Mcl1 can, by itself, cause CLL cells to die, and that this effect might enhance the activity of rituximab,” says first author Rehan Hussain, a postdoctoral fellow with Ohio State's Comprehensive Cancer Center.
Byrd, Hussain and their collaborators conducted this research using cancer cells from 17 CLL patients and ALL cell lines grown in the laboratory.
The investigators placed molecules called small interfering RNA (siRNA) inside the cells and found that the tiny molecules greatly reduced the amount of the survival protein, causing many of the cells to die. The effect was the same even in cells that came from patients with advanced cancer or from patients with tumors that resisted conventional treatment.
When the researchers treated cells with both siRNA and the drug rituximab, the combination killed significantly more leukemia cells than the drug alone. Overall, says Byrd, “Our data indicate that specifically targeting Mcl1 might be effective in the treatment of CLL, particularly when combined with rituximab.”
Funding from the National Cancer Institute, the Leukemia & Lymphoma Society and the D. Warren Brown Foundation supported this research. Byrd is the D. Warren Brown Professor of Leukemia Research and a Clinical Scholar of the Leukemia & Lymphoma Society. The study by researchers at the Ohio State University Comprehensive Cancer Center is published online in the journal Clinical Cancer Research.
Potential New Way To Make A Good Anti-Leukemia Drug Even Better
A recently identified cancer-causing protein makes the anti-leukemia drug imatinib, less effective. By blocking the protein, an international team of researchers was able to slow the spread of leukemia cells in culture.
The study, which will appear online on October 20 in the Journal of Experimental Medicine, suggests that the most effective treatment for leukemia may rely on a combination of targeted drugs, rather than a single miracle drug.
Imatinib is currently the most popular therapy for chronic myeloid leukemia (CML). CML is a type of blood cancer that is most common among middle-aged adults and accounts for 15-20% of all cases of adult leukemia in the western world. Accumulation of cancer cells in the patient's blood causes infections, anemia, and other potentially life-threatening complications.
CML is associated with the abnormal fusion of a portion of chromosome 21 with a cell growth-promoting enzyme called ABL, which makes the enzyme perpetually active. Imatinib slows down the spread of cancer by blocking the enzyme's activity. But the drug doesn't work in everyone and resistance often develops, most likely because the drug only targets mature cells, leaving self-renewing cancer stem cells behind.
Now, Xiaoyan Jiang and a team of researchers from the British Columbia Cancer Agency in Vancouver and other institutions may have discovered what protects the stem cells from imatinib.
The team found that a protein called AHI-1, which has been found in leukemia cells in the past, is highly expressed in CML stem cells. When Zhou and colleagues blocked AHI-1 in cancer cells from imatinib-resistant CML patients, they restored the ability of the drug to kill the cells. The next step, says Jiang is finding a drug that blocks AHI-1, which could potentially be given in combination with imatinib in the future.
The study, which will appear online on October 20 in the Journal of Experimental Medicine, suggests that the most effective treatment for leukemia may rely on a combination of targeted drugs, rather than a single miracle drug.
Imatinib is currently the most popular therapy for chronic myeloid leukemia (CML). CML is a type of blood cancer that is most common among middle-aged adults and accounts for 15-20% of all cases of adult leukemia in the western world. Accumulation of cancer cells in the patient's blood causes infections, anemia, and other potentially life-threatening complications.
CML is associated with the abnormal fusion of a portion of chromosome 21 with a cell growth-promoting enzyme called ABL, which makes the enzyme perpetually active. Imatinib slows down the spread of cancer by blocking the enzyme's activity. But the drug doesn't work in everyone and resistance often develops, most likely because the drug only targets mature cells, leaving self-renewing cancer stem cells behind.
Now, Xiaoyan Jiang and a team of researchers from the British Columbia Cancer Agency in Vancouver and other institutions may have discovered what protects the stem cells from imatinib.
The team found that a protein called AHI-1, which has been found in leukemia cells in the past, is highly expressed in CML stem cells. When Zhou and colleagues blocked AHI-1 in cancer cells from imatinib-resistant CML patients, they restored the ability of the drug to kill the cells. The next step, says Jiang is finding a drug that blocks AHI-1, which could potentially be given in combination with imatinib in the future.
Stop Signal for Leukemia Stem Cells
There are numerous specialized growth factors that are responsible for cells of different tissues of our body to divide and differentiate when needed. These hormone-like factors bind to matching receptors on the surface of their target cells and thus give order for the cell to divide. However, a single genetic alteration can be sufficient for the whole system to get out of control. If, for example, the gene for such a growth factor or for the matching receptor is hyperactive, then the cell permanently receives signals to divide -- and this can result in cancer.
Such defective growth signals play a role in many cancers. Thus, breast cancer cells in about 20 percent of affected women form too many receptors for the Her2/neu growth factor; in bowel cancer doctors frequently find an overproduction of the EGF growth factor.
Jointly with colleagues from France, Canada and the U.S., scientists headed by Professor Dr. Andreas Trumpp of the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) have now discovered that in T-cell acute lymphoblastic leukemia (T-ALL), too, malignant growth is driven by a particular growth factor. In this case, it is the insulin-like growth factor 1 (IGF1) which plays the key role.
The investigators found out that there is an oversupply of IGF1 receptors in T-ALL. The leukemia cells therefore become particularly sensitive to IGF1 signals. When the researchers blocked the IGF1 receptors using specific inhibitors or turned off the gene coding for the receptor, the blood cancer cells ceased to grow. This worked both in murine cancer cells and in human leukemia cells.
However, blockage of the IGF1 signal not only stopped cancer cell growth. Moreover, the dangerous cancer stem cells lost their capability of self-renewal. This was shown by the investigators in a classic experiment called serial transplantation. They transplanted T-ALL cells that formed only small amounts of IGF1 receptors on their surface into mice. Although T-ALL cells normally always cause leukemia in recipient animals, only very few mice developed leukemia after injection of the modified T-ALL. For the team this was the most important clue that leukemia stem cells were either absent or no longer active, because they are the only ones that can initiate leukemia.
"We only need to reduce the level of IGF1 receptors slightly in order to deprive cancer stem cells of their self-renewal capacity. Apparently, leukemia stem cells are particularly dependent on strong IGF1 signals," explained Dr. Hind Medyouf, first author of the article.
Acute lymphoblastic leukemias are the most frequent malignancies in children; however, elderly adults may be affected, too. The group's results open up new prospects for treatment, because substances inhibiting the IGF1 receptor are already available and are currently being tested for other types of cancers such as breast cancer in clinical trials. Andreas Trumpp, a stem cell specialist, explains: „Elderly T-ALL patients have a particularly high recurrence rate after seemingly successful chemotherapy. Inhibition of the IGF1 signaling pathway would target the leukemia stem cells in particular and might therefore prevent recurrence of the cancer."
Such defective growth signals play a role in many cancers. Thus, breast cancer cells in about 20 percent of affected women form too many receptors for the Her2/neu growth factor; in bowel cancer doctors frequently find an overproduction of the EGF growth factor.
Jointly with colleagues from France, Canada and the U.S., scientists headed by Professor Dr. Andreas Trumpp of the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) have now discovered that in T-cell acute lymphoblastic leukemia (T-ALL), too, malignant growth is driven by a particular growth factor. In this case, it is the insulin-like growth factor 1 (IGF1) which plays the key role.
The investigators found out that there is an oversupply of IGF1 receptors in T-ALL. The leukemia cells therefore become particularly sensitive to IGF1 signals. When the researchers blocked the IGF1 receptors using specific inhibitors or turned off the gene coding for the receptor, the blood cancer cells ceased to grow. This worked both in murine cancer cells and in human leukemia cells.
However, blockage of the IGF1 signal not only stopped cancer cell growth. Moreover, the dangerous cancer stem cells lost their capability of self-renewal. This was shown by the investigators in a classic experiment called serial transplantation. They transplanted T-ALL cells that formed only small amounts of IGF1 receptors on their surface into mice. Although T-ALL cells normally always cause leukemia in recipient animals, only very few mice developed leukemia after injection of the modified T-ALL. For the team this was the most important clue that leukemia stem cells were either absent or no longer active, because they are the only ones that can initiate leukemia.
"We only need to reduce the level of IGF1 receptors slightly in order to deprive cancer stem cells of their self-renewal capacity. Apparently, leukemia stem cells are particularly dependent on strong IGF1 signals," explained Dr. Hind Medyouf, first author of the article.
Acute lymphoblastic leukemias are the most frequent malignancies in children; however, elderly adults may be affected, too. The group's results open up new prospects for treatment, because substances inhibiting the IGF1 receptor are already available and are currently being tested for other types of cancers such as breast cancer in clinical trials. Andreas Trumpp, a stem cell specialist, explains: „Elderly T-ALL patients have a particularly high recurrence rate after seemingly successful chemotherapy. Inhibition of the IGF1 signaling pathway would target the leukemia stem cells in particular and might therefore prevent recurrence of the cancer."
How To Design A Cancer-Killing Virus
One new way to treat individuals with cancer that is being developed is the use of viruses that infect and kill cancer cells while leaving normal cells unharmed. These viruses are known as virotherapeutics.
In a new study, David Kirn and colleagues at Jennerex Biotherapeutics, San Francisco, have described the development of a new virotherapuetic with antitumor effects in both mice and rabbits.
After selecting a highly potent strain of poxvirus that was able to traffic to tumors when administered intravenously to mice the authors engineered the virus such that it would target only specific cancer cells -- those with increased expression of a protein known as E2F and/or activation of signaling downstream of a protein known as EGFR.
Further engineering to enable the virus to produce the soluble factor GM-CSF was designed to enhance the induction of anti-tumor immune responses. In addition to its antitumor effects in mice and rabbits, the virotherapeutic showed high selectivity for cancer cells in tumor-bearing rabbits and in human tissue samples, leading the authors to suggest that this virotherapeutic should be tested in clinical trials for the treatment of cancer.
Article: Rational strain selection and engineering creates a broad-spectrum, systemically effective oncolytic poxvirus, JX-963, Journal of Clinical Investigation, October 25, 2007.
In a new study, David Kirn and colleagues at Jennerex Biotherapeutics, San Francisco, have described the development of a new virotherapuetic with antitumor effects in both mice and rabbits.
After selecting a highly potent strain of poxvirus that was able to traffic to tumors when administered intravenously to mice the authors engineered the virus such that it would target only specific cancer cells -- those with increased expression of a protein known as E2F and/or activation of signaling downstream of a protein known as EGFR.
Further engineering to enable the virus to produce the soluble factor GM-CSF was designed to enhance the induction of anti-tumor immune responses. In addition to its antitumor effects in mice and rabbits, the virotherapeutic showed high selectivity for cancer cells in tumor-bearing rabbits and in human tissue samples, leading the authors to suggest that this virotherapeutic should be tested in clinical trials for the treatment of cancer.
Article: Rational strain selection and engineering creates a broad-spectrum, systemically effective oncolytic poxvirus, JX-963, Journal of Clinical Investigation, October 25, 2007.
Combinatorial Therapy Allows Viruses to Destroy Tumors
For several years, researchers have been developing a new approach to treating cancer that uses viruses to infect and kill cancer cells while leaving normal cells unharmed. Recent data have indicated that this approach, which is known as oncolytic virotherapy, has potential.
Now, Richard Vile and colleagues, at the Mayo Clinic, Rochester, have found that this approach can be combined with a standard clinical therapy to provide substantial regression and cure of tumors in mice, leading them to suggest that this combinatorial approach could be of tremendous benefit in the clinic.
Tumors that grow to a certain size need to form new blood vessels if they are to continuing growing and spread to other sites. One of the molecules that controls this new blood vessel growth, VEGF, is the target of drugs used to treat several forms of cancer. In this study, the authors found that modulating VEGF signaling, for example by transiently stopping anti-VEGF therapy in mice harboring cancer cells expressing high levels of VEGF, allowed the cells that line tumor blood vessels to be targeted and killed by viruses.
Importantly, as this approach targets the cells lining tumor blood vessels, rather than specific types of tumor cells, the authors suggest that this combinatorial approach to therapy could be used to treat a wide range of cancers.
The research appears in the Journal of Clinical Investigation.
Now, Richard Vile and colleagues, at the Mayo Clinic, Rochester, have found that this approach can be combined with a standard clinical therapy to provide substantial regression and cure of tumors in mice, leading them to suggest that this combinatorial approach could be of tremendous benefit in the clinic.
Tumors that grow to a certain size need to form new blood vessels if they are to continuing growing and spread to other sites. One of the molecules that controls this new blood vessel growth, VEGF, is the target of drugs used to treat several forms of cancer. In this study, the authors found that modulating VEGF signaling, for example by transiently stopping anti-VEGF therapy in mice harboring cancer cells expressing high levels of VEGF, allowed the cells that line tumor blood vessels to be targeted and killed by viruses.
Importantly, as this approach targets the cells lining tumor blood vessels, rather than specific types of tumor cells, the authors suggest that this combinatorial approach to therapy could be used to treat a wide range of cancers.
The research appears in the Journal of Clinical Investigation.
Unlocking The Body's Defenses Against Cancer
Scientists have discovered a way of allowing healthy cells to take charge of cancerous cells and stop them developing into tumours in what could provide a new approach to treating early-stage cancers.
University of Manchester researchers found that a special type of the chemicals known as 'kinase inhibitors' opened up communication channels on the surface of cells that enabled healthy cells to 'talk' to the cancer cells.
"When we added the chemicals to a mixture of healthy and cancerous cells in a flask the diseased cells stopped multiplying and began acting like normal cells again," said Dr Ian Hampson, who carried out the research with wife Dr Lynne Hampson.
"Further tests revealed that the chemicals helped the cancer cells form connections with surrounding healthy cells that allowed these normal cells to take charge of the mechanism by which cancer cells divide and grow out of control."
Cell division occurs naturally and continuously in human organs and tissue as part of the body's normal repair processes to combat wear and tear but in cancer the cells divide in an uncontrolled way.
Dr Hampson says the findings, published in the British Journal of Cancer, are all the more exciting because the chemicals, which were developed with colleagues at the University of Salford, appear to be relatively non-toxic and the positive effect on the cancer cells persists even when the chemicals are withdrawn.
"When the chemicals were added to a culture containing just cancer cells they had little effect," said Dr Hampson, who is based in Manchester's School of Cancer and Imaging Sciences. "It was only when we added the chemicals to a mixture of cancer cells and normal cells – similar to how you would find them in the body – that growth was suppressed.
"Intriguingly, the connections that allowed the healthy cells to communicate with the cancer cells stayed open even when the kinase inhibitors were removed indicating that a potential drug based on these chemicals could be given as a short course of treatment.
"Furthermore, the chemicals are non-poisonous and do not actually kill cells like conventional cancer therapies, such as chemotherapy and radiotherapy, so if we were able to develop a drug it is likely to have far fewer side-effects."
The team say the next stage of their research will be to find out exactly how the chemicals are able to increase the number of connections between cancer and normal cells. Once this is known, it should be possible to produce a drug based on these chemicals that could hopefully be used in humans.
Dr Lynne Hampson added: "We are currently applying for funding to carry out further research into the biochemistry of how these chemicals cause the effect we have observed. We also intend to investigate the use of different types of cell cultures to assess the potency and range of activity of these agents."
The research was funded by the Association for International Cancer Research, The Humane Research Trust, The Caring Cancer Research Trust, Kidscan and the Cancer Prevention Research Trust.
University of Manchester researchers found that a special type of the chemicals known as 'kinase inhibitors' opened up communication channels on the surface of cells that enabled healthy cells to 'talk' to the cancer cells.
"When we added the chemicals to a mixture of healthy and cancerous cells in a flask the diseased cells stopped multiplying and began acting like normal cells again," said Dr Ian Hampson, who carried out the research with wife Dr Lynne Hampson.
"Further tests revealed that the chemicals helped the cancer cells form connections with surrounding healthy cells that allowed these normal cells to take charge of the mechanism by which cancer cells divide and grow out of control."
Cell division occurs naturally and continuously in human organs and tissue as part of the body's normal repair processes to combat wear and tear but in cancer the cells divide in an uncontrolled way.
Dr Hampson says the findings, published in the British Journal of Cancer, are all the more exciting because the chemicals, which were developed with colleagues at the University of Salford, appear to be relatively non-toxic and the positive effect on the cancer cells persists even when the chemicals are withdrawn.
"When the chemicals were added to a culture containing just cancer cells they had little effect," said Dr Hampson, who is based in Manchester's School of Cancer and Imaging Sciences. "It was only when we added the chemicals to a mixture of cancer cells and normal cells – similar to how you would find them in the body – that growth was suppressed.
"Intriguingly, the connections that allowed the healthy cells to communicate with the cancer cells stayed open even when the kinase inhibitors were removed indicating that a potential drug based on these chemicals could be given as a short course of treatment.
"Furthermore, the chemicals are non-poisonous and do not actually kill cells like conventional cancer therapies, such as chemotherapy and radiotherapy, so if we were able to develop a drug it is likely to have far fewer side-effects."
The team say the next stage of their research will be to find out exactly how the chemicals are able to increase the number of connections between cancer and normal cells. Once this is known, it should be possible to produce a drug based on these chemicals that could hopefully be used in humans.
Dr Lynne Hampson added: "We are currently applying for funding to carry out further research into the biochemistry of how these chemicals cause the effect we have observed. We also intend to investigate the use of different types of cell cultures to assess the potency and range of activity of these agents."
The research was funded by the Association for International Cancer Research, The Humane Research Trust, The Caring Cancer Research Trust, Kidscan and the Cancer Prevention Research Trust.
Aspirin May Lower the Risk of Pancreatic Cancer
The use of aspirin at least once per month is associated with a significant decrease in pancreatic cancer risk, according to results of a large case-control study presented at the AACR 102nd Annual Meeting 2011, held in Orlando, Florida, April 2-6.
Xiang-Lin Tan, Ph.D., M.D., a research fellow at Mayo Clinic in Rochester, Minn., said the findings from this large collaborative study are preliminary and do not encourage widespread use of aspirin for this purpose.
"The results are not meant to suggest everyone should start taking aspirin once monthly to reduce their risk of pancreatic cancer," said Tan. "Individuals should discuss use of aspirin with their physicians because the drug carries some side effects."
For the current study, Tan and colleagues enrolled 904 patients who had documented pancreatic cancer and compared them with 1,224 healthy patients. All patients were at least 55 years old and reported their use of aspirin, NSAIDs and acetaminophen by questionnaire.
Results showed that people who took aspirin at least one day during a month had a 26 percent decreased risk of pancreatic cancer compared to those who did not take aspirin regularly. The effect was also found for those who took low-dose aspirin for heart disease prevention at 35 percent lower risk, according to Tan.
The researchers did not see a benefit from non-aspirin NSAIDs or acetaminophen. "This provides additional evidence that aspirin may have chemoprevention activity against pancreatic cancer," said Tan. He added that more data must be gathered before we can prove a real benefit.
Xiang-Lin Tan, Ph.D., M.D., a research fellow at Mayo Clinic in Rochester, Minn., said the findings from this large collaborative study are preliminary and do not encourage widespread use of aspirin for this purpose.
"The results are not meant to suggest everyone should start taking aspirin once monthly to reduce their risk of pancreatic cancer," said Tan. "Individuals should discuss use of aspirin with their physicians because the drug carries some side effects."
For the current study, Tan and colleagues enrolled 904 patients who had documented pancreatic cancer and compared them with 1,224 healthy patients. All patients were at least 55 years old and reported their use of aspirin, NSAIDs and acetaminophen by questionnaire.
Results showed that people who took aspirin at least one day during a month had a 26 percent decreased risk of pancreatic cancer compared to those who did not take aspirin regularly. The effect was also found for those who took low-dose aspirin for heart disease prevention at 35 percent lower risk, according to Tan.
The researchers did not see a benefit from non-aspirin NSAIDs or acetaminophen. "This provides additional evidence that aspirin may have chemoprevention activity against pancreatic cancer," said Tan. He added that more data must be gathered before we can prove a real benefit.
Regular Aspirin Intake Halves Cancer Risk, Study Finds
Scientists including those from Queen's University have discovered that taking regular aspirin halves the risk of developing hereditary cancers.
Hereditary cancers are those which develop as a result of a gene fault inherited from a parent. Bowel and womb cancers are the most common forms of hereditary cancers. Fifty thousand people in the UK are diagnosed with bowel and womb cancers every year; 10 per cent of these cancers are thought to be hereditary.
The decade-long study, which involved scientists and clinicians from 43 centres in 16 countries and was funded by Cancer Research UK, followed nearly 1,000 patients, in some cases for over 10 years. The study found that those who had been taking a regular dose of aspirin had 50 per cent fewer incidents of hereditary cancer compared with those who were not taking aspirin.
The research focused on people with Lynch syndrome which is an inherited genetic disorder that causes cancer by affecting genes responsible for detecting and repairing damage in the DNA. Around 50 per cent of those with Lynch syndrome develop cancer, mainly in the bowel and womb. The study looked at all cancers related to the syndrome, and found that almost 30 per cent of the patients not taking aspirin had developed a cancer compared to around 15 per cent of those taking the aspirin.
Those who had taken aspirin still developed the same number of polyps, which are thought to be precursors of cancer, as those who did not take aspirin but they did not go on to develop cancer. It suggests that aspirin could possibly be causing these cells to destruct before they turn cancerous.
Over 1,000 people were diagnosed with bowel cancer in Northern Ireland last year; 400 of these died from the disease. Ten per cent of bowel cancer cases are hereditary and by taking aspirin regularly the number of those dying from the hereditary form of the disease could be halved.
Professor Patrick Morrison from Queen's University in Belfast, who led the Northern Ireland part of the study, said: "The results of this study, which has been ongoing for over a decade, proves that the regular intake of aspirin over a prolonged period halves the risk of developing hereditary cancers. The effects of aspirin in the first five years of the study were not clear but in those who took aspirin for between five and ten years the results were very clear."
"This is a huge breakthrough in terms of cancer prevention. For those who have a history of hereditary cancers in their family, like bowel and womb cancers, this will be welcome news. Not only does it show we can reduce cancer rates and ultimately deaths, it opens up other avenues for further cancer prevention research. We aim now to go forward with another trial to assess the most effective dosage of aspirin for hereditary cancer prevention and to look at the use of aspirin in the general population as a way of reducing the risk of bowel cancer.
"For anyone considering taking aspirin I would recommend discussing this with your GP first as aspirin is known to bring with it a risk of stomach complaints, including ulcers."
The research was published online Oct. 28 in The Lancet.
Hereditary cancers are those which develop as a result of a gene fault inherited from a parent. Bowel and womb cancers are the most common forms of hereditary cancers. Fifty thousand people in the UK are diagnosed with bowel and womb cancers every year; 10 per cent of these cancers are thought to be hereditary.
The decade-long study, which involved scientists and clinicians from 43 centres in 16 countries and was funded by Cancer Research UK, followed nearly 1,000 patients, in some cases for over 10 years. The study found that those who had been taking a regular dose of aspirin had 50 per cent fewer incidents of hereditary cancer compared with those who were not taking aspirin.
The research focused on people with Lynch syndrome which is an inherited genetic disorder that causes cancer by affecting genes responsible for detecting and repairing damage in the DNA. Around 50 per cent of those with Lynch syndrome develop cancer, mainly in the bowel and womb. The study looked at all cancers related to the syndrome, and found that almost 30 per cent of the patients not taking aspirin had developed a cancer compared to around 15 per cent of those taking the aspirin.
Those who had taken aspirin still developed the same number of polyps, which are thought to be precursors of cancer, as those who did not take aspirin but they did not go on to develop cancer. It suggests that aspirin could possibly be causing these cells to destruct before they turn cancerous.
Over 1,000 people were diagnosed with bowel cancer in Northern Ireland last year; 400 of these died from the disease. Ten per cent of bowel cancer cases are hereditary and by taking aspirin regularly the number of those dying from the hereditary form of the disease could be halved.
Professor Patrick Morrison from Queen's University in Belfast, who led the Northern Ireland part of the study, said: "The results of this study, which has been ongoing for over a decade, proves that the regular intake of aspirin over a prolonged period halves the risk of developing hereditary cancers. The effects of aspirin in the first five years of the study were not clear but in those who took aspirin for between five and ten years the results were very clear."
"This is a huge breakthrough in terms of cancer prevention. For those who have a history of hereditary cancers in their family, like bowel and womb cancers, this will be welcome news. Not only does it show we can reduce cancer rates and ultimately deaths, it opens up other avenues for further cancer prevention research. We aim now to go forward with another trial to assess the most effective dosage of aspirin for hereditary cancer prevention and to look at the use of aspirin in the general population as a way of reducing the risk of bowel cancer.
"For anyone considering taking aspirin I would recommend discussing this with your GP first as aspirin is known to bring with it a risk of stomach complaints, including ulcers."
The research was published online Oct. 28 in The Lancet.
Attacking Bowel Cancer On Two Fronts
Stem cells in the intestine, which when they mutate can lead to bowel cancers, might also be grown into transplant tissues to combat the effects of those same cancers, the UK National Stem Cell Network (UKNSCN) annual science meeting heard March 31.
Professor Nick Barker of the Institute of Medical Biology in Singapore will explain how he and his team identified that the stem cells which are crucial to maintaining a healthy intestine are also the site at which bowel cancers first begin, and how he also hopes to use healthy stem cells to regenerate tissues to help patients with Crohn's disease and some cancers.
Having discovered a gene that is only turned on in these particular stem cells Professor Barker and his team have been able to isolate the cells in mice and grow small pieces of intestine in the lab. The researchers hope that if they are able to grow larger pieces, they will be able to produce transplant tissues to replace damaged intestines.
Professor Barker explains: "Processing our dinner every day is a tough job so the lining of our intestines quickly get worn out. To keep the intestine working stem cells in little pockets along the surface replace the lining, cell by cell, about once a week.
"We already knew these stem cells existed for a while we didn't know much about them because it was difficult to distinguish them from all of the other types of cells in our intestines. Our team was able to single them out and study them because we discovered a gene that is only turned on in these particular stem cells."
Once the researchers had found this gene they were able to track where the stem cells occur throughout the body finding that, as well as the intestine, the stomach lining and in hair follicles, the cells were also present in bowel tumours.
Professor Barker continues: "We hope that studying these stem cells will be doubly useful: One day we hope to grow large enough pieces in the lab to form replacement tissues for transplant; and by studying the cells we will be able to find new ways to prevent them from mutating and hence leading to cancer.
"Bowel cancer is the third most common type of cancer in England and an estimated 38,000 new cases are diagnosed each year. We know these stem cells are both implicated in causing the cancer but that they also could be useful for treating disease so we hope that studying them will help us to understand how to attack the disease on two fronts.
Professor Nick Barker of the Institute of Medical Biology in Singapore will explain how he and his team identified that the stem cells which are crucial to maintaining a healthy intestine are also the site at which bowel cancers first begin, and how he also hopes to use healthy stem cells to regenerate tissues to help patients with Crohn's disease and some cancers.
Having discovered a gene that is only turned on in these particular stem cells Professor Barker and his team have been able to isolate the cells in mice and grow small pieces of intestine in the lab. The researchers hope that if they are able to grow larger pieces, they will be able to produce transplant tissues to replace damaged intestines.
Professor Barker explains: "Processing our dinner every day is a tough job so the lining of our intestines quickly get worn out. To keep the intestine working stem cells in little pockets along the surface replace the lining, cell by cell, about once a week.
"We already knew these stem cells existed for a while we didn't know much about them because it was difficult to distinguish them from all of the other types of cells in our intestines. Our team was able to single them out and study them because we discovered a gene that is only turned on in these particular stem cells."
Once the researchers had found this gene they were able to track where the stem cells occur throughout the body finding that, as well as the intestine, the stomach lining and in hair follicles, the cells were also present in bowel tumours.
Professor Barker continues: "We hope that studying these stem cells will be doubly useful: One day we hope to grow large enough pieces in the lab to form replacement tissues for transplant; and by studying the cells we will be able to find new ways to prevent them from mutating and hence leading to cancer.
"Bowel cancer is the third most common type of cancer in England and an estimated 38,000 new cases are diagnosed each year. We know these stem cells are both implicated in causing the cancer but that they also could be useful for treating disease so we hope that studying them will help us to understand how to attack the disease on two fronts.
Subscribe to:
Posts (Atom)