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. · Sep 1995
Intraindividual and interindividual differences in metabolites of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in smokers' urine.
This study describes quantitation in smokers' urine of two metabolites of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). The metabolites are 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), which is also a lung carcinogen, and its O-glucuronide (NNAL-Gluc), a presumed detoxification product of NNK. Using updated methodology, levels of NNAL, NNAL-Gluc, and cotinine were determined in the urine of 61 smokers. ⋯ Thus, intraindividual differences in the NNAL-Gluc:NNAL ratio were generally small, whereas interindividual differences were large. Amounts of NNAL, NNAL-Gluc, and cotinine excreted by smokers were constant in 24-h samples obtained over a 3-day period of constant cigarette intake and controlled diet. Levels of NNAL, NNAL-Gluc, and NNAL plus NNAL-Gluc correlated with cotinine in a study of 61 smokers without controlled diet or smoking (r = 0.58; P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Cancer Epidemiol. Biomarkers Prev. · Sep 1995
Randomized Controlled Trial Multicenter Study Clinical TrialDesign and recruitment for retinoid skin cancer prevention (SKICAP) trials. The Southwest Skin Cancer Prevention Study Group.
The retinoid skin cancer prevention (SKICAP) trials are a set of double-blind, randomized, placebo-controlled clinical trials. The SKICAP-actinic keratoses (AK) trial tests the hypothesis that daily supplementation of retinol (25,000 IU) for 5 years reduces the incidence of skin cancers in high-risk individuals, those with a history of greater than ten clinically or pathologically diagnosed AK and, at most, one prior pathologically confirmed cutaneous squamous cell carcinoma (SCC) or basal cell carcinoma (BCC). The SKICAP-SCC/BCC (S/B) trial tests the hypothesis that daily supplementation of retinol (25,000 IU) or 13-cis-retinoic acid (5 or 10 mg) for 3 years reduces skin cancer incidence in very high-risk individuals, those with a history of at least four pathologically confirmed SCCs or BCCs. ⋯ The initial recruitment strategy was referral by dermatologists, but low accrual necessitated the use of other strategies to achieve enrollment goals, which included involving additional clinics and using paid trial-specific advertisements in print and electronic media. Thirteen % of the SKICAP-AK participants and 36% of the SKICAP-S/B participants were enrolled through dermatologist referral, whereas paid advertisements resulted in enrollment of 87% of SKICAP-AK and 43% of SKICAP-S/B participants. A population-based skin cancer registry was used to identify and enroll the remaining 21% of the SKICAP-S/B participants.(ABSTRACT TRUNCATED AT 250 WORDS)
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Cancer Epidemiol. Biomarkers Prev. · Jan 1995
ReviewApproaches to the development and marketing approval of drugs that prevent cancer.
The broad concept of chemoprevention applies to the prevention of clinical cancer by the administration of chemical agents. Current approaches to the development and marketing approval of drugs to prevent cancer are described by a Working Group from the National Cancer Institute and the Food and Drug Administration. A strategy is presented that identifies candidate drugs, with examples that illustrate how drugs are characterized for efficacy through in vitro transformation modulation and mechanistic assays, and in vivo tumor modulation models of carcinogenesis. ⋯ Appropriate subject populations are identified. Phase II trials should emphasize the evaluation of surrogate end point biomarkers that are highly correlated with cancer incidence and may serve as an estimate of cancer incidence reduction. In Phase III trials the interim analysis of a validated surrogate end point of cancer incidence may facilitate timely and cost-effective marketing of efficacious drugs.
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Cancer Epidemiol. Biomarkers Prev. · Jul 1994
Uptake and metabolism of carcinogenic levels of tobacco-specific nitrosamines by Sudanese snuff dippers.
It was recently reported that toombak, a type of snuff used in the Sudan, contained unusually high levels of tobacco-specific nitrosamines. To estimate the internal dose of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) received by individuals who use this type of tobacco, urine from a group of users was analyzed for 2 metabolites of NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its O-glucuronide, NNAL-Gluc. NNK is a strong lung carcinogen believed to contribute to human lung cancer. ⋯ This adduct is believed to be a measure of NNK activation. The levels ranged from 68 to 323 fmol/g hemoglobin [mean, 148 +/- 104 (SD)]. The wide range of adduct levels which were observed suggests that despite similar levels of NNK exposure, there are significant differences in the ability of individuals in this population to activate NNK, as well as potential differences in their cancer risk.
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Cancer Epidemiol. Biomarkers Prev. · Jun 1994
Comparative StudyHepatitis C virus, alcoholic cirrhosis, and hepatocellular carcinoma.
We undertook a retrospective study to determine the prevalence of hepatitis C virus (HCV) and hepatitis B virus (HBV) infection in 81 Caucasian patients with confirmed hepatocellular carcinoma (HCC). Besides HBV and HCV serological markers, HCV RNA and HBV DNA were detected in serum and liver tissue by polymerase chain reaction. Overall, HCV RNA was found in 20 cases (25%), HBV DNA in 21 patients (26%), and coinfection in 3 patients (3%). ⋯ HBV DNA was present in 19% of HCC-AC as compared to 3% of AC and 0% of alcoholic hepatitis. We conclude that the form of HCC in 50% of the patients in a Western European country is related to chronic viral hepatitis. Our data obtained from a group of patients having alcoholic liver disease with or without HCC suggest that the prevalence of HCV RNA or HBV DNA in these populations increases with the severity of hepatic injury.