Mary Beth Terry

DNA methylation in white blood cells: association with risk factors in epidemiologic studies.

Alterations in DNA methylation patterns, both at specific loci and overall in the genome, have been associated with many different health outcomes. In cancer and other diseases, most of these changes have been observed at the tissue level. Data on whether DNA methylation changes in white blood cells (WBC) can serve as a useful biomarker for different health outcomes are much more limited, but rapidly emerging. Epidemiologic studies have reported associations between global WBC methylation and several different cancers including cancers of the colon, bladder, stomach, breast and head and neck, as well as schizophrenia and myelodysplastic syndrome. Evidence for WBC methylation at specific loci and disease risk is more limited, but increasing. Differences in WBC DNA methylation by selected risk factors including demographic (age, gender, race), environmental exposures (benzene, persistent organic pollutants, lead, arsenic, and air pollution), and other risk factors (cigarette smoke, alcohol drinking, body size, physical activity and diet) have been observed in epidemiologic studies though the patterns are far from consistent. Challenges in inferences from the existing data are primarily due to the cross-sectional and small size of most studies to date as well as the differences in results across assay type and source of DNA. Large, prospective studies will be needed to understand whether changes in risk factors are associated with changes in DNA methylation patterns, and if changes in DNA methylation patterns are associated with changes in disease endpoints.

Frequent Promoter Methylation of CDH1, DAPK, RARB, and HIC1 Genes in Carcinoma of Cervix Uteri: Its Relationship to Clinical Outcome

BackgroundCervical cancer (CC), a leading cause of cancer-related deaths in women worldwide, has been causally linked to genital human papillomavirus (HPV) infection. Although a host of genetic alterations have been identified, molecular basis of CC development is still poorly understood.ResultsWe examined the role of promoter hypermethylation, an epigenetic alteration that is associated with the silencing tumor suppressor genes in human cancer, by studying 16 gene promoters in 90 CC cases. We found a high frequency of promoter methylation in CDH1, DAPK, RARB, and HIC1 genes. Correlation of promoter methylation with clinical characteristics and other genetic changes revealed the following: a) overall promoter methylation was higher in more advanced stage of the disease, b) promoter methylation of RARB and BRCA1 predicted worse prognosis, and c) the HIC1 promoter methylation was frequently seen in association with microsatellite instability. Promoter methylation was associated with gene silencing in CC cell lines. Treatment with methylation or histone deacetylation-inhibiting agents resulted in profound reactivation of gene expression.ConclusionsThese results may have implications in understanding the underlying epigenetic mechanisms in CC development, provide prognostic indicators, and identify important gene targets for treatment.

The Long Island Breast Cancer Study Project: Description of a multi-institutional collaboration to identify environmental risk factors for breast cancer

The Long Island Breast Cancer Study Project is a federally mandated, population-based case-control study to determine whether breast cancer risk among women in the counties of Nassau and Suffolk, NY, is associated with selected environmental exposures, assessed by blood samples, self-reports, and environmental home samples. This report describes the collaborative projects background, rationale, methods, participation rates, and distributions of known risk factors for breast cancer by case-control status, by blood donation, and by availability of environmental home samples. Interview response rates among eligible cases and controls were 82.1% (n, = 1,508) and 62.8% (n = 1,556), respectively. Among case and control respondents who completed the interviewer-administered questionnaire, 98.2 and 97.6% self-completed the food frequency questionnaire; 73.0 and 73.3% donated a blood sample; and 93.0 and 83.3% donated a urine sample. Among a random sample of case and control respondents who are long-term residents, samples of dust (83.6 and 83.0%); soil (93.5 and 89.7%); and water (94.3 and 93.9%) were collected. Established risk factors for breast cancer that were found to increase risk among Long Island women include lower parity, late age at first birth, little or no breast feeding, and family history of breast cancer. Factors that were found to be associated with a decreased likelihood that a respondent would donate blood include increasing age and past smoking; factors associated with an increased probability include white or other race, alcohol use, ever breastfed, ever use of hormone replacement therapy, ever use of oral contraceptives, and ever had a mammogram. Long-term residents (defined as 15+ years in the interview home) with environmental home samples did not differ from other long-term residents, although there were a number of differences in risk factor distributions between long-term residents and other participants, as anticipated.

Environmental Toxins and Breast Cancer on Long Island. I. Polycyclic Aromatic Hydrocarbon DNA Adducts

Polycyclic aromatic hydrocarbons (PAH) are potent mammary carcinogens in rodents, but their effect on breast cancer development in women is not clear. To examine whether currently measurable PAH damage to DNA increases breast cancer risk, a population-based case-control study was undertaken on Long Island, NY. Cases were women newly diagnosed with in situ and invasive breast cancer; controls were randomly selected women frequency matched to the age distribution of cases. Blood samples were donated by 1102 (73.0%) and 1141 (73.3%) of case and control respondents, respectively. Samples from 576 cases and 427 controls were assayed for PAH-DNA adducts using an ELISA. The geometric mean (and geometric SD) of the log-transformed levels of PAH-DNA adducts on a natural scale was slightly, but nonsignificantly, higher among cases [7.36 (7.29)] than among controls [6.21 (4.17); P = 0.51]. The age-adjusted odds ratio (OR) for breast cancer in relation to the highest quintile of adduct levels compared with the lowest was 1.51 [95% confidence interval (CI), 1.04-2.20], with little or no evidence of substantial confounding (corresponding multivariate-adjusted OR, 1.49; 95% CI, 1.00-2.21). There was no consistent elevation in risk with increasing adduct levels, nor was there a consistent association between adduct levels and two of the main sources of PAH, active or passive cigarette smoking or consumption of grilled and smoked foods. These data indicate that PAH-DNA adduct formation may influence breast cancer development, although the association does not appear to be dose dependent and may have a threshold effect.

One-Carbon Metabolism, MTHFR Polymorphisms, and Risk of Breast Cancer

Accumulating evidence from epidemiologic studies suggests that risk of breast cancer is reduced in relation to increased consumption of folate and related B vitamins. We investigated independent and joint effects of B vitamin intake as well as two polymorphisms of a key one-carbon metabolizing gene [i.e., methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C] on breast cancer risk. The study uses the resources of a population-based case-control study, which includes 1,481 cases and 1,518 controls. Significant inverse associations between B vitamin intake and breast cancer risk were observed among non-supplement users. The greatest reduction in breast cancer risk was observed among non-supplement users in the highest quintile of dietary folate intake [odds ratio (OR), 0.61; 95% confidence interval (95% CI), 0.41-0.93] as compared with non-supplement users in the lowest quintile of dietary folate intake (high-risk individuals). The MTHFR 677T variant allele was associated with increased risk of breast cancer (P, trend = 0.03) with a multivariate-adjusted OR of 1.37 (95% CI, 1.06-1.78) for the 677TT genotype. The 1298C variant allele was inversely associated with breast cancer risk (P, trend = 0.03), and was likely due to the linkage of this allele to the low-risk allele of 677C. The MTHFR-breast cancer associations were more prominent among women who did not use multivitamin supplements. Compared with 677CC individuals with high folate intake, elevation of breast cancer risk was most pronounced among 677TT women who consumed the lowest levels of dietary folate (OR, 1.83; 95% CI, 1.13-2.96) or total folate intake (OR, 1.71; 95% CI, 1.08-2.71). From a public heath perspective, it is important to identify risk factors, such as low B vitamin consumption, that may guide an effective prevention strategy against the disease.

Better preservation of immune function after laparoscopic-assisted vs . open bowel resection in a murine model

PURPOSE: We evaluated cell-mediated immune function after laparoscopic-assisted and open bowel resection in rats by measuring delayed-type hypersensitivity responses to keyhole limpet hemocyanin (KLH) and phytohemagglutinin (PHA). METHODS: Male Sprague-Dawley rats (n=120) were sensitized to 1 mg of KLH ten days before investigations. Rats were challenged preoperatively, immediately postoperatively, and on postoperative day (POD) 2 with an intradermal injection of 0.3 mg of KLH and 0.2 mg of PHA (at different sites). Averages of two measures of perpendicular diameters (taken 24 and 48 hours postchallenge) were used to calculate the area of induration using the formula for the area of an ellipse, A=(D1/2×D2/2)×π. Anesthesia control animals underwent no procedure (n=40). Open resection group underwent ligation and resection of the cecum (length=2 cm) through a 7 cm midline incision (n=40). In the laparoscopic-assisted resection group, under CO2 pneumoperitoneum (4–6 mmHg), the cecum was identified, dissected free, and exteriorized through a 4 mm port. The cecum was then ligated and resected extracorporeally (n=40). RESULTS: Preoperative responses to both KLH and PHA were the same in all three groups. Furthermore, within each group, postoperative responses were similar. When groups were compared, the anesthesia group responses were significantly greater than the open resection group responses at all time points (P<0.05 for all comparisons). Laparoscopic-assisted resection group responses differed from control at only two of eight postoperative measures. Laparoscopic resection group responses were significantly greater than open resection group responses to challenge with both KLH and PHA on POD1 (P<0.02, for both comparisons) and POD 4 (P<0.05, for both comparisons). CONCLUSIONS: Postoperative cell-mediated immune function is better preserved after laparoscopic-assisted bowel resection than after open resection as assessed by skin antigen testing.

Genomic DNA Methylation among Women in a Multiethnic New York City Birth Cohort

One plausible mechanism for the environment to alter cancer susceptibility is through DNA methylation. Alterations in DNA methylation can lead to genomic instability and altered gene transcription. Genomic DNA methylation levels have been inversely associated with age, suggesting that factors throughout life may be associated with declines in DNA methylation. Using information from a multiethnic New York City birth cohort (born between 1959 and 1963), we examined whether genomic DNA methylation, measured in peripheral blood mononuclear cells, was associated with smoking exposure and other epidemiologic risk factors across the life course. Information on prenatal and childhood exposures was collected prospectively through 1971, and information on adult exposures and blood specimens were collected in adulthood from 2001 to 2007. Methylation levels of leukocyte DNA were determined using a [3H]-methyl acceptance assay where higher values of disintegrations per minute per microgram DNA indicate less DNA methylation. Genomic methylation of leukocyte DNA differed by ethnicity (66% of Blacks, 48% of Whites, and 29% of Hispanics were above the median level of disintegrations per minute per microgram DNA; P = 0.03). In multivariable modeling, DNA methylation was statistically significantly associated with maternal smoking during pregnancy, longer birth length, later age at menarche, nulliparity, and later age at first birth. These data, if replicated in larger samples, suggest that risk factors across the life course may be associated with DNA methylation in adulthood. Larger studies and studies that measure within-individual changes in DNA methylation over time are a necessary next step. (Cancer Epidemiol Biomarkers Prev 2008;17(9):2306–10)

Short Telomere Length and Breast Cancer Risk: A Study in Sister Sets

Telomeres consist of a tandem repeats of the sequence TTAGGG at the ends of chromosomes and play a key role in the maintenance of chromosomal stability. Previous studies indicated that short telomeres are associated with increased risk for human bladder, head and neck, lung, and renal cell cancer. We investigated the association between white blood cell telomere length and breast cancer risk among 268 family sets (287 breast cancer cases and 350 sister controls). Telomere length was assessed by quantitative PCR. The mean telomere length was shorter in cases (mean, 0.70; range, 0.03-1.95) than in unaffected control sisters (mean, 0.74; range, 0.03-2.29), but no significant difference was observed (P = 0.11). When subjects were categorized according to the median telomere length in controls (0.70), affected sisters had shorter telomeres compared with unaffected sisters after adjusting for age at blood donation and smoking status [odds ratio (OR), 1.3; 95% confidence interval (95% CI), 0.9-1.8], but the association was not statistically significant. The association by quartile of telomere length (Q4 shortest versus Q1 longest) also supported an increase in risk from shorter telomere length, although the association was not statistically significant (OR, 1.6; 95% CI, 0.9-2.7). This association was more pronounced among premenopausal women (OR, 2.1; 95% CI, 0.8-5.5) than postmenopausal women (OR, 1.3; 95% CI, 0.5-3.6 for Q4 versus Q1). If these associations are replicated in larger studies, they provide modest epidemiologic evidence that shortened telomere length may be associated with breast cancer risk.

Risks of breast, ovarian, and contralateral breast cancer for BRCA1 and BRCA2 mutation carriers

Importance The clinical management of BRCA1 and BRCA2 mutation carriers requires accurate, prospective cancer risk estimates. Objectives To estimate age-specific risks of breast, ovarian, and contralateral breast cancer for mutation carriers and to evaluate risk modification by family cancer history and mutation location. Design, Setting, and Participants Prospective cohort study of 6036 BRCA1 and 3820 BRCA2 female carriers (5046 unaffected and 4810 with breast or ovarian cancer or both at baseline) recruited in 1997-2011 through the International BRCA1/2 Carrier Cohort Study, the Breast Cancer Family Registry and the Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer, with ascertainment through family clinics (94%) and population-based studies (6%). The majority were from large national studies in the United Kingdom (EMBRACE), the Netherlands (HEBON), and France (GENEPSO). Follow-up ended December 2013; median follow-up was 5 years. Exposures BRCA1/2 mutations, family cancer history, and mutation location. Main Outcomes and Measures Annual incidences, standardized incidence ratios, and cumulative risks of breast, ovarian, and contralateral breast cancer. Results Among 3886 women (median age, 38 years; interquartile range [IQR], 30-46 years) eligible for the breast cancer analysis, 5066 women (median age, 38 years; IQR, 31-47 years) eligible for the ovarian cancer analysis, and 2213 women (median age, 47 years; IQR, 40-55 years) eligible for the contralateral breast cancer analysis, 426 were diagnosed with breast cancer, 109 with ovarian cancer, and 245 with contralateral breast cancer during follow-up. The cumulative breast cancer risk to age 80 years was 72% (95% CI, 65%-79%) for BRCA1 and 69% (95% CI, 61%-77%) for BRCA2 carriers. Breast cancer incidences increased rapidly in early adulthood until ages 30 to 40 years for BRCA1 and until ages 40 to 50 years for BRCA2 carriers, then remained at a similar, constant incidence (20-30 per 1000 person-years) until age 80 years. The cumulative ovarian cancer risk to age 80 years was 44% (95% CI, 36%-53%) for BRCA1 and 17% (95% CI, 11%-25%) for BRCA2 carriers. For contralateral breast cancer, the cumulative risk 20 years after breast cancer diagnosis was 40% (95% CI, 35%-45%) for BRCA1 and 26% (95% CI, 20%-33%) for BRCA2 carriers (hazard ratio [HR] for comparing BRCA2 vs BRCA1, 0.62; 95% CI, 0.47-0.82; P=.001 for difference). Breast cancer risk increased with increasing number of first- and second-degree relatives diagnosed as having breast cancer for both BRCA1 (HR for ≥2 vs 0 affected relatives, 1.99; 95% CI, 1.41-2.82; P<.001 for trend) and BRCA2 carriers (HR, 1.91; 95% CI, 1.08-3.37; P=.02 for trend). Breast cancer risk was higher if mutations were located outside vs within the regions bounded by positions c.2282-c.4071 in BRCA1 (HR, 1.46; 95% CI, 1.11-1.93; P=.007) and c.2831-c.6401 in BRCA2 (HR, 1.93; 95% CI, 1.36-2.74; P<.001). Conclusions and Relevance These findings provide estimates of cancer risk based on BRCA1 and BRCA2 mutation carrier status using prospective data collection and demonstrate the potential importance of family history and mutation location in risk assessment.

Chromosomal amplifications, 3q gain and deletions of 2q33-q37 are the frequent genetic changes in cervical carcinoma

BackgroundCarcinoma of uterine cervix is the second most common cancers among women worldwide. Combined radiation and chemotherapy is the choice of treatment for advanced stages of the disease. The prognosis is poor, with a five-year survival rate ranging from about 20–65%, depending on stage of the disease. Therefore, genetic characterization is essential for understanding the biology and clinical heterogeneity in cervical cancer (CC).MethodsWe used a genome-wide screening method – comparative genomic hybridization (CGH) to identify DNA copy number changes in 77 patients with cervical cancer. We applied categorical and survival analyses to analyze whether chromosomal changes were related to clinico-pathologic characteristics and patients survival.ResultsThe CGH analysis revealed a loss of 2q33-q37 (57.1%), gain of 3q (54.5%) and chromosomal amplifications (20.77%) as frequent genetic changes. A total of 15 amplified chromosomal sites were detected in 16 cases that include 1p31, 2q32, 7q22, 8q21.2-q24, 9p22, 10q21, 10q24, 11q13, 11q21, 12q15, 14q12, 17p11.2, 17q22, 18p11.2, and 19q13.1. Recurrent amplified sites were noted at 11q13, 11q21, and 19q13.1. The genomic alterations were further evaluated for prognostic significance in CC patients, and we did not find any correlation with a number of clinical or histological parameters. The tumors harboring HPV18 exhibited higher genomic instability compared to tumors with HPV 16.ConclusionsThis study demonstrated that 2q33-q37 deletions, 3q gains and chromosomal amplifications as characteristic changes in invasive CC. These genetic alterations will aid in the identification of novel tumor suppressor gene(s) at 2q33-q37 and oncogenes at amplified chromosomal sites. Molecular characterization of these chromosomal changes utilizing the current genomic technologies will provide new insights into the biology and clinical behavior of CC.