Statin Use Not Associated With Colorectal Cancer Risk
Regular use of cholesterol-lowering drugs called statins is not associated with a reduced risk of colorectal cancer, according to a population-based case-control study.
Laboratory tests of statins have found anticancer effects on colon cancer cells. One case-control study of people found that use of statins for at least 5 years reduced the risk of colorectal cancer by 50 percent. To further understand the possible association between statin use and colorectal cancer risk, Patricia F. Coogan, Sc.D., and colleagues at the Boston University School of Medicine used the Massachusetts Cancer Registry and hospital tumor registries to identify 1809 patients with colorectal cancer. They interviewed each patient, gathering data on medical history and medication use, including statins and non-steroidal anti-inflammatory drugs (NSAIDs), such as asprin. The researchers also used town registries to identify 1809 people without colorectal cancer who were similar in age, sex, and town precinct.
The researchers initially found a modest association between statin use and decreased colorectal cancer risk. However, after they took into account how often people took NSAIDs, the association between statin use and colorectal cancer risk disappeared. No association was found among recent, continuing, or discontinued users of statins, nor was there an association at various doses of statins. The researchers did find that use of NSAIDs alone was associated with a 21 percent decreased risk of colorectal cancer. They also found an association between statin use and reduced risk of stage IV colorectal cancer, a finding, the authors say, requires further confirmation.
Contact: Gina Digravio, Media Relations Manager, Boston University Medical School, 617-638-8491, gina.digravio@bmc.org
Role of Folate Unclear in Breast Cancer Risk
There's no clear relationship between folate intake or blood folate levels and breast cancer risk, a new study suggests.
In the last 20 years, some studies have suggested that low folate intake is associated with an increased risk of several cancers, including breast cancer. Additional studies have found that that the increase in breast cancer risk associated with alcohol consumption can be reduced by adequate folate intake. Susanna C. Larsson, of the Karolinska Institute in Stockholm, and colleagues performed a meta-analysis of nine prospective studies and 14 case-control studies of folate intake and risk of breast cancer.
Overall, there was no association between total folate intake or blood folate levels with breast cancer risk. They did find an association between dietary folate intake and reduced breast cancer risk among the case-control studies; however, no such association was found among the prospective studies. Their findings also suggest that high folate intake might be associated with a reduced risk of breast cancer in women with moderate or high consumption of alcohol.
"There was evidence from prospective studies that adequate folate intake may attenuate the increased risk of breast cancer associated with alcohol consumption," the authors write. "Large prospective studies that investigate interactions between folate and other nutrients involved in one-carbon metabolism, alcohol consumption, and functional polymorphisms in genes encoding folate-metabolizing enzymes are needed to further clarify the role of folate in breast cancer etiology."
Contact: Susanna Larsson, PhD, Karolinska Institute, Stockholm, phone: +46 8 524 860 59, e-mail: Susanna.Larsson@ki.se
Study Identifies Hypothyroidism Among Patients Taking Sunitinib
Abnormal thyroid function is common among patients with metastatic renal cell carcinoma taking a new drug called sunitinib, and these patients' thyroid levels should be routinely monitored, a new study finds.
Sunitinib was recently approved for the treatment of advanced renal cell carcinoma. A common side effect of the drug is fatigue, and abnormal thyroid function can cause weakness and fatigue. Brian I. Rini, M.D., of the Cleveland Clinic Taussig Cancer Center, and colleagues decided to measure thyroid function in patients taking sunitinib. They reviewed medical records of 66 patients treated in clinical trials of the drug for whom thyroid function tests were available. Fifty-six (85 percent) of the patients had one or more thyroid function blood test abnormalities, and 47 of those patients had clinical signs or symptoms of hypothyroidism. In 17 patients, doctors attempted to correct the hypothyroidism using thyroid replacement hormones, and symptoms improved in 9 of those patients. Routine monitoring of thyroid function blood tests is warranted in patients with renal cell carcinoma taking sunitinib, the authors conclude.
Contact: Erinne Dyer, Cleveland Clinic, 216-444-8168, dyere@ccf.org
Study Suggests Role for Y Chromosome in Prostate Cancer
A new study finds that, among a group of men in Israel, men with only daughters had a 40 percent higher risk of prostate cancer than men with at least one son. The study raises the possibility that some mutation or variant on the Y chromosome may be involved in prostate cancer.
Although several studies have identified risk factors for prostate cancer and found some gene mutations that are associated with the disease, none of these can account for large numbers of prostate cancer cases. Some studies have suggested that prostate cancer risk may be associated with alterations on the X or Y chromosomes.
Because alterations on the sex chromosomes might affect the probability of having sons or daughters, Susan Harlap, M.D., of Columbia University in New York, decided to study cancer incidence and offspring among men participating in the Jerusalem Perinatal Study. During the study period, 712 men were diagnosed with prostate cancer. Compared with men who had at least one son, men with only daughters had a 40 percent increased risk of prostate cancer. Men with no daughters had no increase or decrease in prostate cancer risk compared with men with offspring of both sexes.
"Overall, our findings are consistent with hypotheses that tie Y chromosome loci to prostate cancer, although other explanations cannot be excluded," they write.
Contact: Stephanie Berger; Columbia University Office of Public Affairs, 212-305-4372, sb2247@columbia.edu
Arsenic Triggers Unique Mechanism in Rare Leukemia
There are few treatments for a rare cancer called acute promyelocytic leukemia (APL). Arsenite is a form of arsenic that's particularly effective against this cancer. In a new study, researchers identify a novel mechanism by which arsenite acts in APL cells.
APL is caused by a translocation of chromosomes 15 and 17 that forms a fusion protein between two genes called promyelocytic leukemia protein (PML) and retinoic acid receptor alpha (RAR-alpha). This fusion protein prevents certain blood cells from maturing and leads to an accumulation of these immature leukemia cells. In the new study, Sutisak Kitareewan, Ph.D., of Dartmouth Medical School, and colleagues find that arsenite destabilizes lysosomes in APL cells. Lysosomes contain enzymes that can break down various cellular components. Destabilized lysosomes release enzymes that degrade the faulty PML/RAR-alpha protein, a step that often leads to the death of the cancerous APL cells.
Contact: Susan E. Knapp, Dartmouth Medical School, 603-646-3661, Susan.E.Knapp@Dartmouth.edu
Study Examines Drug Delivery With Liposomes
Several chemotherapy drugs can only be given at certain doses because they're highly toxic to healthy cells, and at those doses, the concentration of the drug that reaches cells in the tumor may be quite low. Scientists have been investigating the use of liposomes, hollow spheres of fat molecules, to deliver chemotherapy drugs directly to tumors. These liposomes melt and release their contents when exposed to heat.
In a new study, Ana M. Ponce and Mark W. Dewhirst, D.V.M., Ph.D., of Duke University Medical Center, and colleagues injected doxorubicin-containing liposomes into rats bearing fibrosarcomas. The researchers monitored the rats continuously using magnetic resonance imaging to watch how the liposomes distributed in the body. They also tracked whether it was most effective to inject the liposomes before, during, or before and during heating of the tumor, which triggers the liposomes to dissolve and release the doxorubicin inside.
Based on their results, the researchers conclude that the drug distribution was most effective when the liposomes were given while the tumor was being heated.
Contact: Becky Levine, Duke University Medical Center News Office, (919) 660-1308, Levin005@mc.duke.edu
EMBARGOED FOR RELEASE: 2 JANUARY 16:00 EST
Also in the January 3 JNCI:
- Study calculates patient time costs associated with cancer care, http://www.eurekalert.org/emb_releases/2007-01/jotn-cp122706.php
- Study examines risk of soft tissue sarcomas in hereditary retinoblastoma survivors, http://www.eurekalert.org/emb_releases/2007-01/jotn-er122706.php
Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage. Visit the Journal online at http://jncicancerspectrum.oxfordjournals.org/.
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JNCI Journal of the National Cancer Institute