Faculty Bibliography

We examined a spectrum of genotoxic and other outcomes in 41 butadiene-polymer production workers and 38 nonexposed controls, in China, to explore the role of butadiene in human carcinogenesis. Among butadiene-exposed workers, median air exposure was 2 ppm (6-h TWA), due largely to intermittent high-level exposures. Compared to unexposed subjects, butadiene-exposed workers had greater levels of hemoglobin N-(2,3,4-trihydroxybutyl)valine (THBVal) adducts (P<0.0001), and adduct levels tended to correlate, among butadiene-exposed workers, with air measures (P=0.03). Butadiene-exposed workers did not differ, however, from unexposed workers with respect to frequency of uninduced or diepoxybutane-induced sister chromatid exchanges, aneuploidy as measured by fluorescence in situ hybridization of chromosomes 1, 7, 8 and 12, glycophorin A variants or lymphocyte hprt somatic mutation. Also among the exposed, greater THBVal levels were not associated with increases in uninduced sister chromatid exchanges, aneuploidy, glycophorin A, or hprt mutations. Butadiene-exposed workers had greater lymphocyte (P=0.002) and platelet counts (P=0.07) and lymphocytes as a percent of white blood cells were moderately correlated with greater THBVal levels (Spearman's rho=0.32, P=0.07). Among butadiene-exposed workers, several serum cytokines correlated with THBVal adduct levels. Overall, the study demonstrated exposure to butadiene in these workers, by a variety of short-term and long-term measures, but did not show specific genotoxic effects, at the chromosomal or gene levels, related to that exposure

In this study, the authors sought to determine the effects of length and clarity on response rates and data quality for two food frequency questionnaires (FFQs): the newly developed 36-page Diet History Questionnaire (DHQ), designed to be cognitively easier for respondents, and a 16-page FFQ developed earlier for the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. The PLCO Trial is a 23-year randomized controlled clinical trial begun in 1992. The sample for this substudy, which was conducted from January to April of 1998, consisted of 900 control and 450 screened PLCO participants aged 55-74 years. Controls received either the DHQ or the PLCO FFQ by mail. Screenees, who had previously completed the PLCO FFQ at baseline, were administered the DHQ. Among controls, the response rate for both FFQs was 82%. Average amounts of time needed by controls to complete the DHQ and the PLCO FFQ were 68 minutes and 39 minutes, respectively. Percentages of missing or uninterpretable responses were similar between instruments for questions on frequency of intake but were approximately 3 and 9 percentage points lower (p < or = 0.001) in the DHQ for questions on portion size and use of vitamin/mineral supplements, respectively. Among screenees, response rates for the DHQ and the PLCO FFQ were 84% and 89%, respectively, and analyses of questions on portion size and supplement use showed few differences. These data indicated that the shorter FFQ was not better from the perspective of response rate and data quality, and that clarity and ease of administration may compensate for questionnaire length

OBJECTIVES: To characterize the role of demographic and clinical parameters in the measurements of prostate-specific antigen (PSA), free PSA (fPSA), and percent free PSA (%fPSA). METHODS: This was a cohort study of volunteers to a randomized screening trial. A central laboratory determined PSA and fPSA for the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. A baseline evaluation of free and total PSA was done for 7183 white, black, Asian, Hispanic, and other male volunteers, aged 55 to 74 years. Comparisons were made across racial and ethnic groups and across a set of clinical parameters from a baseline questionnaire. RESULTS: The median levels of serum PSA were less than 2.1 ng/mL in each age-race grouping of the study participants. The levels of free and total PSA were higher in black (n = 868, 12%) participants than in white (n = 4995, 70%) and Asian (n = 849, 11.8%) participants. Individuals who identified themselves as ethnically Hispanic (n = 339, 4.7%) had median PSA levels higher than whites who were not Hispanic. The free and total PSA levels increased with age, particularly among men 70 to 74 years old. However, the %fPSA levels showed less variation among the four racial groups or by age. The free and total PSA levels were higher among those who had a history of benign prostatic disease. CONCLUSIONS: Demographic (age and race/ethnicity) and clinical (history of benign prostatic disease) variables had a moderate effect on the measures of PSA and fPSA and very little effect on %fPSA

BACKGROUND: Use of alcohol and tobacco are the major risk factors for cancers of the oral cavity and pharynx in most of the world. A heritable component to oral carcinoma risk also has been suggested, although only limited data are available on familial aggregation of this disease. METHODS: A population-based case-control study of 342 subjects with carcinomas of the oral cavity and pharynx (oral carcinoma) and 521 controls was conducted in Puerto Rico. The relation between family history of carcinomas of the oral cavity, the upper aerodigestive tract (UADT), and other selected sites with risk of oral carcinoma was explored using logistic regression modeling techniques. RESULTS: Risk of oral carcinoma was elevated for subjects reporting a first-degree relative with carcinoma of the oral cavity (odds ratio [OR], 2.5; 95% confidence interval [CI], 0.8-8.0) or any UADT carcinoma (OR, 2.6; 95% CI, 1.4-4.8). The increased risk associated with family history of UADT carcinoma tended to be greatest for subjects with known risk factors (i.e., heavy consumption of alcohol and/or tobacco and infrequent intake of raw fruits and vegetables) and with oral carcinoma diagnoses at ages younger than 65 years. CONCLUSIONS: These findings are consistent with a heritable component to oral carcinoma, although shared lifestyle risk factors may be partially involved

BACKGROUND: Quantitative evaluations of benzene-associated risk for cancer have relied primarily on findings from a cohort study of highly exposed U.S. rubber workers. An epidemiologic investigation in China (NCI/CAPM study) extended quantitative evaluations of cancer risk to a broader range of benzene exposures, particularly at lower levels. METHODS: We review the evidence implicating benzene in the etiology of hematopoietic disorders, clarify methodologic aspects of the NCI/CAPM study, and examine the study in the context of the broader literature on health effects associated with occupational benzene exposure. RESULTS: Quantitative relationships for cancer risk from China and the U.S. show a relatively smooth increase in risk for acute myeloid leukemia and related conditions over a broad dose range of benzene exposure (below 200 ppm-years mostly from the China study and above 200 ppm-years mostly from the U.S. study). CONCLUSIONS: Risks of acute myeloid leukemia and other malignant and nonmalignant hematopoietic disorders associated with benzene exposure in China are consistent with other information about benzene exposure, hematotoxicity, and cancer risk, extending evidence for hematopoietic cancer risks to levels substantially lower than had previously been established. Published 2001 Wiley-Liss, Inc

Blood samples are an excellent source of large amounts of genomic DNA. However, alternative sources are often needed in epidemiological studies because of difficulties in obtaining blood samples. This report evaluates the buccal cytobrush and alcohol-containing mouthwash protocols for collecting DNA by mail. Several DNA extraction techniques are also evaluated. The study was conducted in two phases. In phase 1, we compared cytobrush and mouthwash samples collected by mail in two different epidemiological studies: (a) cytobrush samples (n = 120) from a United States case-control study of breast cancer; and (b) mouthwash samples (n = 40) from a prospective cohort of male United States farmers. Findings from phase 1 were confirmed in phase 2, where we randomized cytobrush (n = 28) and mouthwash (n = 25) samples among participants in the breast cancer study to directly compare both collection methods. The median human DNA yield determined by hybridization with a human DNA probe from phenol-chloroform extracts was 1.0 and 1.6 microg/2 brushes for phases 1 and 2, respectively, and 27.5 and 16.6 microg/mouthwash sample for phases 1 and 2, respectively. Most (94-100%) mouthwash extracts contained high molecular weight DNA (>23 kb), in contrast to 55-61% of the brush extracts. PCR success rates for amplification of beta-globin gene fragments (268, 536, and 989 bp) were similar for cytobrush and mouthwash phenol-chloroform extracts (range, 94.4-100%). Also, we obtained high success rates in determining the number of CAG repeats in the androgen receptor gene, characterizing tetranucleotide microsatellites in six gene loci, and screening for mutations in the BRCA1/2 genes in a subset of phenol-chloroform DNA extracts. Relative to DNA extracted by phenol-chloroform from cytobrush samples, DNA extracted by NaOH had lower molecular weight, decreased PCR success rates for most assays performed, and unreliably high spectrophotometer readings for DNA yields. In conclusion, although DNA isolated from either mouthwash or cytobrush samples collected by mail from adults is adequate for a wide range of PCR-based assays, a single mouthwash sample provides substantially larger amounts and higher molecular weight DNA than two cytobrush samples

OBJECTIVES: To explore whether dietary factors contribute to the risk of multiple myeloma and the two-fold higher incidence among blacks compared to whites in the United States. METHODS: Data from a food-frequency questionnaire were analyzed for 346 white and 193 black subjects with multiple myeloma, and 1086 white and 903 black controls who participated in a population-based case-control study of multiple myeloma in three areas of the United States. RESULTS: Elevated risks were associated with obese vs. normal weight (OR = 1.9, 95% confidence interval (CI) = 1.2-3.1 for whites and OR = 1.5, 95% CI = 0.9-2.4 for blacks), while the frequency of obesity was greater for black than white controls. Reduced risks were related to frequent intake of cruciferous vegetables (OR = 0.7, 95% CI = 0.6-0.99) and fish (OR = 0.7, 95% CI = 0.5-0.9) in both races combined, and to vitamin C supplements in whites (OR = 0.6, 95% CI = 0.5-0.9) and blacks (OR = 0.8, 95% CI = 0.5-1.4), with the frequency of vitamin supplement use being greater for white than black controls. However, frequent intake of vitamin C from food and supplements combined was associated with a protective effect in whites (OR = 0.6, 95% CI = 0.4-0.9), but not blacks (OR = 1.2, 95% CI = 0.8-2.1). CONCLUSIONS: The greater use of vitamin C supplements by whites and the higher frequency of obesity among blacks may explain part of the higher incidence of multiple myeloma among blacks compared to whites in the United States. In addition, the increasing prevalence of obesity may have contributed to the upward trend in the incidence of multiple myeloma during recent decades

Urinary benzene (UB) was investigated as a biomarker of exposure among benzene-exposed workers and unexposed subjects in Shanghai, China. Measurements were performed via headspace solid phase microextraction of 0.5 ml of urine specimens followed by gas chromatography-mass spectrometry. This assay is simple and more sensitive than other methods (detection limit 0.016 microg benzene/l urine). The median daily benzene exposure was 31 p.p.m. (range 1.65-329 p.p.m.). When subjects were divided into controls (n = 41), those exposed to < or =31 p.p.m. benzene (n = 22) and >31 p.p.m. benzene (n = 20), the median UB levels were 0.069, 4.95 and 46.1 microg/l, respectively (Spearman r = 0.879, P < 0.0001). A linear relationship was observed between the logarithm of UB and the logarithm of benzene exposure in exposed subjects according to the following equation: ln(UB, microg/l) = 0.196 + 0.709 ln (exposure, p.p.m.) (r = 0.717, P < 0.0001). Considering all subjects, linear relationships were also observed between the logarithm of UB and the corresponding logarithms of four urinary metabolites of benzene, namely t,t-muconic acid (r = 0.938, P < 0.0001), phenol (r = 0.826, P < 0.0001), catechol (r = 0.812, P < 0.0001) and hydroquinone (r = 0.898, P: < 0.0001). Ratios of individual metabolite levels to total metabolites versus UB provide evidence of competitive inhibition of CYP450 enzymes leading to increased production of phenol and catechol at the expense of hydroquinone and muconic acid. Among control subjects UB was readily detected with a mean level of 0.145 microg/l (range 0.027-2.06 microg/l), compared with 5.63 microg/l (range 0.837-26.38 microg/l) in workers exposed to benzene below 10 p.p.m. (P < 0.0001). This suggests that UB is a good biomarker for exposure to low levels of benzene

BACKGROUND: An increased risk of exposure to pesticides for pancreatic cancer has been suggested in a number of epidemiologic studies. METHODS: Cases (N = 484), aged 30-79 years, were diagnosed in 1986-1989. Controls (N = 2,095) were a random sample of the general population. Information on usual occupation and potential confounding factors was obtained. A job-exposure matrix (JEM) approach was used to estimate the level of occupational exposure to pesticides. RESULTS: A significant trend in risk with increasing exposure level of pesticides was observed, with ORs of 1.3 and 1.4 for low and moderate/high exposure levels, respectively. Excess risks were found for occupational exposure to fungicides (OR = 1.5) and herbicides (OR = 1.6) in the moderate/high level after adjustment for potential confounding factors. An increased risk for insecticide exposure was disappeared after adjustment for fungicide and herbicide exposures. Results of our occupation-based analysis were consistent with those from the JEM-based analysis. CONCLUSIONS: Our results suggest that pesticides may increase risk of pancreatic cancer, and indicate the need for investigations that can evaluate risk by specific chemical exposures. Published 2001 Wiley-Liss, Inc

The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, which is randomizing 74,000 screening arm participants (37,000 men, 37,000 women; ages 55-74) and an equal number of nonscreened controls, is a unique setting for the investigation of the etiology of cancer and other diseases and for the evaluation of potential molecular markers of early disease. At entry, baseline information is collected by questionnaire on dietary intake, tobacco and alcohol use, reproductive history (for women), family history of cancer, use of selected drugs, and other selected risk factors. Blood samples collected at the baseline screening exam are aliquoted to serum, plasma, red blood cell, and buffy coat fractions. At the next two annual screening visits, serum samples are collected. At the third annual reexamination, cryopreserved whole blood is obtained, in addition to serum, plasma, red blood cell, and buffy coat fractions. At the fourth and fifth years, serum, plasma, and buffy coat are collected. All blood samples are shipped to a central repository for long-term storage at -70 degrees C. Dietary questionnaires and buccal cells for DNA analysis are obtained from nonscreened controls. Cancer cases are identified through annual follow-up questionnaires, and all deaths are identified through vital status tracing mechanisms. Procedures are being developed to obtain archival pathologic material for selected cases of cancer and related diseases. Initial investigations are focusing on the etiology of colorectal cancer and on the operative characteristics of tests for the early detection of colorectal and prostate cancer