Obesity has been associated with an increased risk of breast cancer among postmenopausal women, but the mechanism for this association has not been established. A new study suggests that the risk increase may result from an associated increase in the production of estrogens. Timothy J. Key, D.Phil., of the University of Oxford, and his colleagues from the Endogenous Hormones and Breast Cancer Collaborative Group analyzed data from eight prospective studies of postmenopausal women and found that breast cancer risk increased with increasing body mass index (a measure of height with respect to weight). However, after adjusting for estrogens, the risk was substantially reduced, suggesting that the increase in breast cancer risk with increasing body mass index is largely the result of the associated increase in estrogens.
Contact: Peter Flynn or Steve Palmer, Cancer Research U.K., 44-20-7061-8300; Karen Carter Mallet, Fox Chase Cancer Center, 215-728- 2700, k_carter@fccc.edu.
Heavier Men May Have a Lower Risk of Prostate Cancer
Under certain conditions, heavier men have a lower risk of developing prostate cancer than men who weigh less, according to a new study. Edward Giovannucci, M.D., Sc.D., of the Harvard School of Public Health in Boston, and his colleagues examined 2,896 cases of prostate cancer in men participating in the Health Professionals Follow-Up Study. They found that men with a higher body mass index had a lower risk of prostate cancer than men with a lower body mass index, but only if they were younger than age 60 or had a family history of prostate cancer. Such an association was not seen in men with sporadic prostate cancers.
Contact: Kevin Myron, Harvard School of Public Health, 617-432-3952, kmyron@hsph.harvard.edu.
Heavier, Taller Women May Have a Higher Risk of Ovarian Cancer
Women who were overweight or obese as adolescents or young adults appear to have an increased risk of ovarian cancer, according to a new study. The study also found a positive association between height and ovarian cancer. Anders Engeland, Ph.D., of the Norwegian Institute of Public Health, and colleagues followed more than 1 million Norwegian women ages 14 to 74 to examine the relationship between body mass index, height, and risk of ovarian cancer. They found that women who were overweight or obese during adolescence or as young adults had a higher risk of ovarian cancer than women with a medium body mass index. Among women younger than age 60, height was also positively associated with a risk of ovarian cancer, particularly endometrioid ovarian cancer.
Risk of Testicular Cancer Determined by Early Environmental Exposures
A new study has found that Finnish men who immigrated to Sweden have a risk of testicular cancer that is comparible with that of men in Finland, suggesting that risk of testicular cancer is determined by environmental exposures early in life. Anders Ekbom, M.D., Ph.D., of the Karolinska Hospital in Stockholm, and colleagues examined the incidence of testicular cancer among 93,172 Finnish men who immigrated to Sweden between 1969 and 1996. The researchers found that Finnish immigrants had a lower incidence of testicular cancer than the Swedish general population and that their risk of testicular cancer was comparable with that of the Finnish general population. Neither age at immigration nor duration of stay in Sweden had any effect on the risk. "The findings are compatible with the hypothesis that lifetime risk of testicular cancer is determined early in life, possible before birth," the authors conclude.
Study Reevaluates Role of Carcinogen-Activating Enzyme
Previous studies in cell cultures suggested that the enzyme CYP12A activates metabolites of the carcinogen ABP, which in turn form DNA adducts that are associated with the development of bladder cancer. But a new study in mice does not appear to support this model. Instead, Yutaka Tsuneoka and Daniel W. Nebert, M.D. of the University of Cincinnati Medical Center, found that mice expressing CYP1A2 had fewer DNA adducts after ABP treatment than similarly treated mice that did not express CYP12A. The authors conclude that either CYP1A2 is not the major metabolic activator of ABP or that other enzymes metabolically activate ABP.
Contact: Dama Kimmon, University of Cincinnati Medical Center, 513-558-4553, dama.kimmon@uc.edu.
New Analysis Doubles Previous Estimates of Hereditary Adrenal Gland Tumors
A review in this issue of the Journal suggests that up to 30% of pheochromocytomas (rare tumors of the adrenal gland) are hereditary--a percentage more than double that previously estimated. In the review, Jennifer Bryant and Katherine L. Nathanson, M.D., of the University of Pennsylvania, and their colleagues examine the data on the association of germline mutations with pheochromocytomas. They say that given the frequency of these mutations, consideration should be given to genetic counseling for all patients with the disease, particular those with a family history of pheochromocytoma, multifocal disease, or a diagnosis before age 50.
Contact: David March, University of Pennsylvania, 215-615-3353, david.march@uphs.upenn.edu.
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.
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JNCI Journal of the National Cancer Institute