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. · Apr 1997
Arylamine N-acetyltransferase 1 (NAT1) and 2 (NAT2) polymorphisms in susceptibility to bladder cancer: the influence of smoking.
Aromatic amines are involved in the etiology of bladder cancer. These compounds are acetylated by N-acetyltransferase 1 (NAT1) and 2 (NAT2), and epidemiological studies have shown that the slow NAT2 acetylator phenotype is associated with increased risk of bladder cancer and may be associated with decreased risk of colorectal cancer. By using PCR-RFLP analyses to identify three known slow acetylator alleles (M1, M2, and M3) and the wild-type, or fast, allele, the NAT2 genotypes were determined. ⋯ The NAT1 and GSTM1 genotypes were not associated with increased risk of bladder cancer among smokers. Analyses of genetic combinations of NAT1/NAT2 as potential risk factors for bladder cancer seem to indicate that the normal NAT1/fast NAT2 genotype may be a protective genotype compared with the other genotype combinations. Analyses of genetic combinations of NAT2/GSTM1 did not reveal any combination of NAT2 and GSTM1 genotypes associated with increased bladder cancer risk.
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Cancer Epidemiol. Biomarkers Prev. · Apr 1997
Racial disparity in the incidence and case-fatality of colorectal cancer: analysis of 329 United States counties.
In the United States, blacks have higher death rates from colon cancer than whites, and the survival disparity may be due in part to differences in screening programs and acute medical care in counties with a high concentration of blacks. We studied 148,947 Medicare beneficiaries with newly diagnosed colorectal cancer in 1989-1991 who resided in the 329 most populous counties in the United States to determine the relationship of race and county racial composition to cancer incidence and survival. Counties were divided into quartiles based on proportion of blacks in the population, and aggregate incidence and 2-year case-fatality rates were compared within and between quartiles. ⋯ When counties were grouped into three different geographic areas, racial disparity in survival was observed in all regions. The variability between groups of counties in colon cancer incidence and mortality for both white and black patients may suggest differences at the county level in screening and treatment. However, consistent racial disparity within county quartiles may reflect persistent deficiencies in access to and quality of care for black patients.
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Cancer Epidemiol. Biomarkers Prev. · Mar 1997
Randomized Controlled Trial Comparative Study Clinical TrialThe effect of wheat bran fiber and calcium supplementation on rectal mucosal proliferation rates in patients with resected adenomatous colorectal polyps.
Colorectal cancers continue as the second most common cause of death from cancer in the United States. Only a few prospective, randomized clinical trials have been performed to evaluate the potential preventive effects of dietary fiber or calcium in patients with an increased risk for the development or recurrence of colorectal cancer. We designed and conducted a double-blinded, placebo-controlled randomized trial involving supplementation of fiber and calcium intake and measurements of [3H]thymidine labeling index (LI) percentages in rectal mucosal biopsies obtained from patients with resected colorectal adenomas to examine the potential mechanisms by which dietary interventions might reduce colorectal cancer risk. ⋯ Neither the wheat bran fiber nor the calcium carbonate supplements significantly reduced [3H]thymidine LI percentages in rectal mucosal crypts (total or compartmental analysis) or 24-h in vitro outgrowth cultures at either 3 or 9 months of daily supplementation in the 93 evaluable participants. We conclude that 9 months of high-dose wheat bran fiber and calcium carbonate supplementation in study participants with a history of recently resected colorectal adenomas does not have a significant effect on cellular proliferation rates in rectal mucosal biopsies, comparing 3- and 9-month results to baseline results. Ultimately, there is great need for the evaluation of these two different nutrient interventions in the setting of Phase III studies wherein adenomatous polyp recurrence, rather than a rectal mucosal biomarker, serves as the primary end point.
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Cancer Epidemiol. Biomarkers Prev. · Feb 1997
Analysis of human urine for pyridine-N-oxide metabolites of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, a tobacco-specific lung carcinogen.
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent pulmonary carcinogen in rodents and is believed to be a causative factor for lung cancer in smokers. NNK also may be involved in oral cancer etiology in users of smokeless tobacco products. Pyridine-N-oxidation of NNK and its major metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), produces NNK-N-oxide and NNAL-N-oxide, respectively, which are detoxification products of NNK metabolism and are excreted in the urine of rodents and primates. ⋯ However, PEITC also could have inhibited pyridine-N-oxidation of NNK and NNAL. The urine of these smokers was analyzed for NNAL-N-oxide. The results demonstrated that watercress consumption had no effect on levels of NNAL-N-oxide in urine, supporting the conclusion that PEITC does inhibit the metabolic activation of NNK in humans.
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Cancer Epidemiol. Biomarkers Prev. · Sep 1996
Comparative StudyDifferential patterns of serum biomarkers of immune activation in human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis, and adult T-cell leukemia/lymphoma.
Adult T-cell leukemia/lymphoma (ATL) and human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are associated with differing patterns of immune dysfunction. Biomarkers of immune activation may correlate with perturbations of immune function associated with these diseases. We conducted a pilot cross-sectional study to assess four candidate biomarkers of immune activation. beta 2-microglobulin, neopterin, tryptophan, and kynurenine levels were assayed in stored sera from asymptomatic, human T-cell leukemia virus type I (HTL V-I)-seronegative (HTLV-I-) and HTLV-I-seropositive (HTLV-I+) individuals, and ATL and HAM/TSP patients previously enrolled in seroepidemiological studies in Jamaica. ⋯ In Cox proportional hazards regression modeling, neopterin and tryptophan were found to be independent predictors of survival among ATL patients. This study demonstrates a differential pattern of biomarkers of immune activation among ATL and HAM/TSP patients compared to HTLV-I- and HTLV-I+ individuals. Neopterin and tryptophan may be useful clinical indicators of disease severity and prognosis among HAM/TSP and ATL patients.