Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology
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Cancer Epidemiol. Biomarkers Prev. · May 2001
Clinical Trial Controlled Clinical TrialThe interaction between microsomal epoxide hydrolase polymorphisms and cumulative cigarette smoking in different histological subtypes of lung cancer.
Microsomal epoxide hydrolase (mEH) is involved in the metabolism of environmental and tobacco carcinogens. Smaller studies found inconsistent results in the relationship between mEH polymorphisms and lung cancer risk. We investigated the two polymorphisms of mEH in 974 Caucasian lung cancer patients and 1142 controls using PCR-RFLP techniques. ⋯ When pack-years = 28.5, the OR was 1.00 (95% CI, 0.76-1.32), and when pack-years = 80, the OR decreased to 0.65 (95% CI, 0.42-1.00). When cases were stratified according to histological subtypes, the interaction between mEH genotype and cumulative smoking was statistically significant (P < 0.01) for the 222 squamous cell carcinoma cases, whereas it was not significant (P = 0.18) for the 432 adenocarcinoma cases. In conclusion, cumulative cigarette smoking plays a pivotal role in the association between mEH polymorphisms and lung cancer risk, altering the direction of risk (in the case of the very low activity genotype) from a risk factor in nonsmokers to a relatively protective factor in heavy smokers.
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Cancer Epidemiol. Biomarkers Prev. · May 2001
Risk factors for subsequent invasive breast cancer and breast cancer death after ductal carcinoma in situ: a population-based case-control study in Sweden.
In a case-control study derived from a cohort of 4661 women with a primary carcinoma in situ of the breast, we investigated age at diagnosis, mode of detection, tumor characteristics, and primary therapy, as prognostic factors for developing invasive breast cancer or dying from breast cancer. From all of the women with a primary carcinoma in situ reported to the Swedish Cancer Registry from 1960 through 1992, we selected as cases all of the women with a ductal carcinoma in situ who later died of breast cancer (n = 39) or who developed a subsequent invasive cancer in either breast (n = 118). From this cohort, we also selected controls matched to the cases by year of diagnosis and health care region. ⋯ The risk pattern by treatment category differed between those who had an ipsilateral invasive cancer and those who either had a contralateral cancer or died from breast cancer. The driving forces behind local and generalized disease may differ. Because confounding by indication may influence the effects of different treatments, the results should be interpreted with caution.
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Cancer Epidemiol. Biomarkers Prev. · May 2001
Comparative StudyLifestyle determinants of 5alpha-reductase metabolites in older African-American, white, and Asian-American men.
Men with higher endogenous 5alpha-reductase activity may have higher prostate cancer risk. This hypothesis raises two questions: (a) Could racial differences in 5alpha-reductase activity explain the observed racial differences in prostate cancer risk? and (b) Could a man reduce his activity level by modifying his lifestyle? To address these questions, we measured two hormonal indices of 5alpha-reductase activity [serum levels of androstane-3alpha-17beta-diol glucuronide (3alpha-diol G) and androsterone glucuronide (AG)] in healthy, older African-American, white, and Asian-American men, who are at high, intermediate, and low prostate cancer risk, respectively. We also examined associations between these metabolite levels and such lifestyle characteristics as body size and physical activity as well as select aspects of medical history and family history of prostate cancer. ⋯ Mean levels of AG, adjusted for age, were 44.1 ng/ml in African-Americans, 44.9 ng/ml in whites, and 37.5 ng/ml in Asian-Americans (Asian-Americans versus whites, P < 0.001). In conclusion, older African-American and white men have similar levels of these two indices of 5alpha-reductase activity, and these levels are higher than those of older Asian-American men. This difference may be related to the lower prostate cancer risk in Asian-Americans.