Renal cell carcinoma, occupational pesticide exposure and modification by glutathione S-transferase polymorphisms.

This study investigated associations between occupational pesticide exposure and renal cell carcinoma (RCC) risk. To follow-up on a previous report by Buzio et al., we also considered whether this association could be modified by glutathione S-transferase M1 and T1 (GSTM1 and GSTT1) genotypes. About 1097 RCC cases and 1476 controls from Central and Eastern Europe were interviewed to collect data on lifetime occupational histories. Occupational information for jobs held for at least 12 months duration was coded for pesticide exposures and assessed for frequency and intensity of exposure. GSTM1 and GSTT1 gene deletions were analyzed using TaqMan assays. A significant increase in RCC risk was observed among subjects ever exposed to pesticides [odds ratio (OR): 1.60; 95% confidence interval (CI): 1.00-2.55]. After stratification by genotypes, increased risk was observed among exposed subjects with at least one GSTM1 active allele (OR: 4.00; 95% CI: 1.55-10.33) but not among exposed subjects with two GSTM1 inactive alleles compared with unexposed subjects with two inactive alleles (P-interaction: 0.04). Risk was highest among exposed subjects with both GSTM1 and GSTT1 active genotypes (OR: 6.47; 95% CI: 1.82-23.00; P-interaction: 0.02) compared with unexposed subjects with at least one GSTM1 or T1 inactive genotype. In the largest RCC case-control study with genotype information conducted to date, we observed that risk associated with pesticide exposure was exclusive to individuals with active GSTM1/T1 genotypes. These findings further support the hypothesis that glutathione S-transferase polymorphisms can modify RCC risk associated with occupational pesticide exposure.

Glutathione S-transferase polymorphisms, cruciferous vegetable intake and cancer risk in the Central and Eastern European Kidney Cancer Study.

High consumption of cruciferous vegetables has been associated with reduced kidney cancer risk in many studies. Isothiocyanates, thought to be responsible for the chemopreventive properties of this food group, are conjugated to glutathione by glutathione S-transferases (GSTs) before urinary excretion. Modification of this relationship by host genetic factors is unknown. We investigated cruciferous vegetable intake in 1097 cases and 1555 controls enrolled in a multicentric case-control study from the Czech Republic, Poland, Romania and Russia. To assess possible gene-diet interactions, genotyped cases (N = 925) and controls (N = 1247) for selected functional or non-synonymous polymorphisms including the GSTM1 deletion, GSTM3 3 bp deletion (IVS6 + 22-AGG) and V224I G>A substitution, GSTT1 deletion and the GSTP1 I105V A>G substitution. The odds ratio (OR) for low (less than once per month) versus high (at least once per week) intake of cruciferous vegetables was 1.29 [95% confidence interval (CI): 1.02-1.62; P-trend = 0.03]. When low intake of cruciferous vegetables (less than once per month) was stratified by GST genotype, higher kidney cancer risks were observed among individuals with the GSTT1 null (OR = 1.86; 95% CI: 1.07-3.23; P-interaction = 0.05) or with both GSTM1/T1 null genotypes (OR = 2.49; 95% CI: 1.08-5.77; P-interaction = 0.05). These data provide additional evidence for the role of cruciferous vegetables in cancer prevention among individuals with common, functional genetic polymorphisms.

Nitrated and oxidized plasma proteins in smokers and lung cancer patients.

Cigarette smoking is a cause of lung cancer and other respiratory diseases. Oxidants either present in cigarette smoke and/or formed in the lung of smokers may trigger oxidative and nitrative damage to DNA and cellular components, contributing to carcinogenesis. We have used immunodot and Western blot analyses to measure nitrated (nitrotyrosine-containing) and oxidized (carbonyl-containing) proteins in plasma samples collected from 52 lung cancer patients and 43 control subjects (heavy and light smokers, nonsmokers with or without exposure to environmental tobacco smoke). The levels of nitrated proteins were significantly higher in lung cancer patients than in controls (P = 0.003). On the other hand, the levels of oxidized proteins were significantly higher in smokers than in nonsmokers (P < 0.001). Western-blot analyses showed the presence of two to five nitrated proteins and one oxidized protein. Using immunoprecipitation and Western-blot analyses with eight different antibodies against human plasma proteins, we identified fibrinogen, transferrin, plasminogen, and ceruloplasmin as nitrated proteins and fibrinogen as the only oxidized protein present in human plasma of lung cancer patients and smokers. Our results indicate that cigarette smoking increases oxidative stress and that during lung cancer development, formation of reactive nitrogen species results in nitration and oxidation of plasma proteins.

Lung cancer risk in nonsmokers and GSTM1 and GSTT1 genetic polymorphism.

Glutathione S-transferase (GST) polymorphism may contribute to the individual variability in detoxifying lung carcinogens. This effect might be particularly relevant at low-level exposure to environmental carcinogens, such as in nonsmokers exposed to environmental tobacco smoke (ETS). We conducted a case-control study among 122 nonsmoking lung cancer cases and 121 nonsmoking controls from eight countries. Information on environmental exposures was obtained through a personal interview. The presence of GSTM1 and GSTT1 genes was determined using multiplex PCR. GSTM1-positive samples were then analyzed for *1A and *1B polymorphism using an allele-specific amplification-PCR method. GSTM1*2 (null) individuals had an odds ratio (OR) of lung cancer of 1.5 [95% confidence interval (CI), 0.9-2.7]; the risk associated with this genotype was higher for cases with squamous and small cell carcinomas (OR, 2.3; 95% CI, 0.9-6.1) than for cases with adenocarcinomas. It was also elevated in individuals with long-term exposure to indoor wood combustion (OR, 3.1; 95% CI, 0.9-9.9), in subjects who mainly lived in a rural setting (OR, 3.6; 95% CI, 1.0-13), and in cases exposed to occupational carcinogens (OR, 10.7; 96% CI, 0.4-260) but not in subjects exposed to ETS. GSTT1*2 subjects did not show a risk of lung cancer. Our study suggests that the effect of GSTM1 polymorphism in nonsmokers is similar to that found in smokers. It does not seem to interact with ETS exposure, although we cannot exclude that it does in association with exposure to other specific environmental carcinogens.

p53 mutations and exposure to environmental tobacco smoke in a multicenter study on lung cancer.

Biomarker data may provide a way to strengthen the link between environmental tobacco smoke (ETS) exposure and lung cancer shown in epidemiological studies. We conducted a multicenter case-control study to investigate the association between ETS exposure and lung cancer in never-smokers using p53 mutations as a biomarker of tobacco-related carcinogenesis. Paraffin-embedded tissue or fresh tissue samples from 91 never-smokers and 66 smokers with histologically confirmed lung cancer and interview data about smoking habits and ETS exposure were analyzed for mutations in the p53 gene. Statistical analysis was performed using multivariate logistic regression. Among the lifelong nonsmokers, the overall mutation prevalence was 10% (nine cases). Among 48 never-smokers ever exposed to spousal ETS, 13% (six cases) showed mutations. Smokers exhibited 17 (26%) mutations. A 3-fold [odds ratio, 2.9; 95% confidence interval (CI), 1.2-7.2] increased risk of p53 mutation was observed for smokers as compared with all never-smokers combined (i.e., irrespective of ETS exposure). The increase was 4.4-fold (95% CI, 1.2-16.2) when compared with never-smokers without ETS exposure. Among never-smokers, the risk of mutation was doubled (odds ratio, 2.0; 95% CI, 0.5-8.7) for exposure to spousal ETS only, based on 6 exposed cases with mutation and 42 exposed cases without mutation. The risk was 1.5 (95% CI, 0.2-8.8) for those ever exposed to spousal or workplace ETS as compared with those never exposed to spousal or workplace ETS. For smokers, the most common mutation type was G:C to T:A transversion (31%), whereas G:C to A:T transitions were predominant among never smokers (57%). In conclusion, our study indicates a significant 3-4-fold increased risk of p53 mutation in smoking lung cancer cases, and it suggests that mechanisms of lung carcinogenesis in ETS-exposed never-smokers include mutations in the p53 gene, similar to that seen in smokers. However, the mutation patterns observed also suggest a difference between smokers and never-smokers. Clearly, additional investigations of the role of p53 mutation as a biomarker for tobacco-related carcinogenesis, including that related to ETS, are indicated.

Exposure to environmental tobacco smoke and risk of adenocarcinoma of the lung.

We conducted a case-control study of adenocarcinoma of the lung and exposure to environmental tobacco smoke (ETS) in 7 countries. We interviewed 70 cases of adenocarcinoma of the lung and 178 population or hospital controls. All subjects had smoked fewer than 400 cigarettes in their lifetimes. Ever exposure to ETS from the parents during childhood was associated with a decreased risk [odds ratio (OR) 0.6, 95% confidence interval (CI) 0.3-1.2], and there was a suggestion of a decreasing trend in risk with increasing duration of exposure. Ever exposure to ETS from the spouse was not associated with an increased risk (OR 1.0, 95% CI 0.5-1.8), while the OR of ever exposure to ETS at the workplace was 1.5 (95% CI 0.8-3.0). For both exposure sources, an increased risk was observed among the highly exposed, and the OR among those with the highest duration of exposure to ETS from the spouse or at the workplace was 1.8 (95% CI 0.5-6.2). A similar risk was estimated for current exposure to ETS from either source. Our results confirm previous reports of a weak effect of adult ETS exposure on risk of adenocarcinoma of the lung. Bias and confounding cannot be excluded as explanations for the apparent decrease in risk from childhood exposure.

4-Hydroxy-1-(3-pyridyl)-1-butanone-hemoglobin adducts as biomarkers of exposure to tobacco smoke: validation of a method to be used in multicenter studies.

Hemoglobin (Hb) adducts of 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB), a metabolite of two tobacco-specific nitrosamines [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and N'-nitrosonornicotine], were measured as biomarkers of exposure to tobacco smoke as part of a study on genetic alterations and susceptibility to lung cancer among nonsmokers. HPB-Hb adducts were measured after collection of RBCs by Ficoll gradient in six collaborating centers, release of HPB by alkaline hydrolysis from Hb, clean-up by solid-phase extraction, and analysis of an electron-capturing derivative by gas chromatography-electron capture mass spectrometry. Prior to analysis of samples from study subjects, the reproducibility of this approach was validated in blood from donors. The coefficient of variation of reproducibility of paired aliquots from five samples ranged from 7 to 25%; the within-sample reproducibilities of four and eight aliquots were 4 and 16%, respectively. The study subjects consisted of 18 smokers and 52 never-smokers. HPB-Hb adduct levels were significantly higher (P = 0.02) in smokers (26 +/- 13 fmol HPB/g Hb) than in never-smokers (20 +/- 8 fmol HPB/g Hb). There was no difference between sexes. These results suggest that the level of HPB-Hb adducts, measured using a method modified to facilitate use in multicenter studies, can be a useful biomarker of exposure to tobacco smoke.

Mortality in a cohort of Russian fertilizer workers.

OBJECTIVES: The study evaluated the mortality of workers exposed to precursors of N-nitroso compounds in a Russian fertilizer plant. METHODS: Workers employed at least two years between 1945 and 1985 in production departments or other services were included in the cohort, which comprised 2039 men and 2957 women followed from 1965 to 1990. The standardized mortality ratios (SMR) were calculated using cause-specific death rates for the Moscow region as reference. An internal comparison was carried out using Poisson regression modeling. Exposure to arsenic, nitrogen oxides, and sulfur dioxide was estimated from an industrial hygiene survey. RESULTS: The production and other workers had no excess of mortality from all causes or all neoplasms. However the male production workers had excess mortality from all cancers combined (SMR 143) and lung cancer (SMR 186) after a latency period of > or = 20 years. Men with the highest exposure to nitrogen oxides had a twofold increase in mortality from stomach cancer, with a marginally significant increasing trend between stomach cancer and cumulative exposure to nitrogen oxides for both genders. Excess mortality from all cancers and stomach cancer was found for the worker with the highest average exposure to arsenic, and excess lung cancer mortality could be attributed to exposure to arsenic. CONCLUSIONS: The investigation showed a weak association between employment in a fertilizer production plant and increased mortality from cancer. The results somewhat support the hypothesis that occupational exposure to precursors of N-nitroso compounds increases the risk of stomach cancer mortality, as does exposure to arsenic.

Enhanced expression of 1p32 and 1p22 fragile sites in lymphocytes in cutaneous malignant melanomas.

Frequency and distribution of 5-fluorodeoxyuridine (5-FdU) plus caffeine-induced fragile sites on chromosomes of peripheral blood lymphocytes (PBL) from 10 patients with cutaneous melanoma were studied in comparison with 10 PBL samples from normal donors of corresponding sex and age. The total number of breaks showed a significant difference among individuals in both groups, however, the average frequencies of 5-FdU plus caffeine-induced, as well as spontaneous damages in PBL from melanoma patients, were higher than those from healthy volunteers. The analysis of the breakpoint distribution showed a statistically significant increase in the expression of several fragile sites. The highest enhancement was observed at 1p32 and 1p22 sites (p less than 0.001). Earlier, the increase in the expression of 1p32 fragile sites was reported for neuroblastoma patients. We believe that enhanced expression of fragile sites in 1p may play a yet-unknown pathogenetic role in the development of some neuroectodermal tumors.