Biomedical subjects

Matthew Bonner

Publications and source records attributed to Matthew Bonner.

3 recordsLinked to original sources

PubMed2006

Cancer incidence among pesticide applicators exposed to metolachlor in the Agricultural Health Study.

Metolachlor is one of the most widely used herbicides in the United States. We evaluated the incidence of cancer among pesticide applicators exposed to metolachlor in the Agricultural Health Study, a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina. A total of 50,193 pesticide applicators were included. Detailed information on pesticide exposure and lifestyle factors was obtained from self-administered enrollment questionnaires completed between 1993 and 1997; average length of follow-up was 7.33 years. Two metolachlor exposure metrics were used : (i) lifetime days personally mixed or applied metolachlor and (ii) intensity-weighted lifetime days (lifetime days x an intensity level). Poisson regression analysis was used to estimate relative risks (RR) and 95% confidence intervals (95%CI) for cancer subtypes by tertiles of metolachlor exposure. No clear risk for any cancer subtype was found for exposure to metolachlor. A significantly decreased RR was found for prostate cancer in the highest category of lifetime days exposure (RR = 0.59; 95%CI, 0.39-0.89) and in the second highest category of intensity-weighted lifetime days exposure (RR = 0.66; 95%CI, 0.45-0.97); however, the test for trend was not significant for either exposure metric. A nonsignificantly increased risk was found for lung cancer with lifetime days exposure in the highest category (RR = 2.37; 95%CI, 0.97-5.82, p-trend = 0.03) but not with intensity-weighted lifetime days. Given the widespread use of metolachlor and the frequent detection of metolachlor in both surface and ground water, future analyses of the AHS will allow further examination of long-term health effects, including lung cancer and the less common cancers.

Acetamides↗

PubMed2006

p53 Mutation analysis in breast tumors by a DNA microarray method.

The p53 gene acts as a regulator of cell growth and DNA repair in normal cells; inactivation of the gene seems to lead to cancer. It is the most commonly mutated gene in human cancers, and a high-throughput sequencing method is needed for cancer etiology studies using large sample sets. In our population-based case-control study of breast cancer, the p53 gene was amplified by PCR for 392 subjects from seven hospitals in Western New York using the Affymetrix GeneChip technology. One hundred thirty-eight (35%) of the breast tumors had p53 mutations, of which 88% were located in exons 5 to 8. New hotspots were identified at codons 179, 195, 196, 213, 217, 249, 254, 278, 281, and 298, and previously reported hotspots were found at codons 175, 248, and 273. Manual sequencing for exons 5 to 9 of the p53 gene was done for 139 tumors to validate the Affymetrix assay. The two methods had 100% concordance for mutations detectable by the Affymetrix assay. We also successfully assayed paraffin-embedded breast and lung tumors from as early as 1958 and employed a nested PCR strategy to improve weak PCR amplification. To have statistical power, the investigation of gene environment interactions and cancer requires a large number of tumor analyses, which are frequently only available from archived tissue from multiple sources. We have shown the utility of the Affymetrix GeneChip method under these challenging conditions and provided new data for the mutational spectra of breast cancer in a population-based study.

Breast Neoplasms↗

PubMed2004

Diet and alcohol consumption in relation to p53 mutations in breast tumors.

There is evidence linking alcohol consumption to p53 mutations in tumors, considerable evidence linking alcohol consumption with risk of breast cancer and some evidence that alcohol and folate consumption interact to affect risk. Further, while there is some indication that oxidation may play a role in breast cancer etiology, there has been little examination of an association of oxidative stress with p53 mutations. We examined several dietary components related to one-carbon metabolism and antioxidants to determine if these factors were related to the prevalence of p53 mutations in breast tumors. We conducted a case-control study of primary, histologically confirmed breast cancer in western New York. Controls <65 were selected from drivers license lists; those > or =65 were selected from Health Care Finance Administration lists. p53 mutations in archived tumor blocks were identified in exons 2-11 and flanking intron sequences. Usual dietary intake was assessed by interview regarding intake in the previous 2 years; alcohol consumption was queried for 2, 10 and 20 years in the past. Our data were consistent with increased likelihood of tumors with p53 mutations for premenopausal breast cancer with increased alcohol intake 10 or 20 years previous; for intake of 16 or more drinks per month in the period 20 years before the interview compared with non-drinkers, the OR was 5.25, 95% CI 1.48-18.58. For postmenopausal women, there was increased likelihood of tumors with p53 mutations among women with higher folate. Antioxidant nutrients were not differentially related to p53 mutations. These results indicate that there may be heterogeneity in breast tumors, as indicated by differences in associations for those with or without p53 mutations, and that causal pathways for these nutrients may vary for pre- and postmenopausal women. For premenopausal women, alcohol consumption in the past was associated with p53 mutations.

Adult↗