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Sholom Wacholder

Publications and source records attributed to Sholom Wacholder.

At least 37 records · Page 2Linked to original sources
PubMed2005

Towards improved biomarker studies of cervical neoplasia: effects of precolposcopic procedures on gene expression patterns.

Among tumor sites, cervical cancer offers an ideal model for investigating differences in gene expression associated with transitions from normal to precancer and invasion to cancer. To evaluate the validity of assessing gene expression in cervical tissues acquired in a clinical setting, we investigated whether standard procedures, namely the application of acetic acid and/or Lugol's iodine, employed for the visualization of colposcopically directed biopsies, altered patterns in oligonucleotide (oligo) arrays. We compared microarray profiles from six women, each with three adjacent tissue samples removed from benign hysterectomy specimens and treated as follows: immediately frozen, acetic acid application only, acetic acid, and Lugol's iodine. Of the 22,464 original spots on the microarray, 4,850 spots were expressed at detectable levels for further evaluation upon data normalization and filtration. For each spot, the difference between topical applications was computed, and P values were calculated using a bivariate T2 test. Upon adjustment for multiple comparisons using both the Holm's and Hochberg's procedures as well as the False Discovery Rate (Benjamini-Hochberg and Benjamini-Yeuketili [BY]), we failed to identify genes differentially expressed and conclude that standard precolposcopic procedures do not substantially affect the overall gene expression patterns in the normal cervix.

Artifacts↗
PubMed2005

Semiquantitative human papillomavirus type 16 viral load and the prospective risk of cervical precancer and cancer.

We examined whether higher human papillomavirus type 16 (HPV16) viral load predicted risk of cervical intraepithelial neoplasia 3 (CIN3) or cancer (together termed > or =CIN3) within a cohort of 20,810 women followed for 10 years with cytologic screening. Semiquantitative viral load for HPV16 was measured on baseline cervicovaginal specimens using a type-specific hybridization probe test with signal amplification. An increased risk of > or =CIN3 associated with higher HPV16 viral load was found only among cytologically negative women in early follow-up, suggesting that these cases were related to the detection of prevalent lesions missed at baseline. Women with higher HPV16 viral load were more likely to undergo ablative treatment during follow-up than those with lower viral load (P(trend) = 0.008), possibly diminishing any additional risk for > or =CIN3 attributable to higher HPV16 viral loads.

Adolescent↗
PubMed2005

PCR testing of pooled longitudinally collected cervical specimens of women to increase the efficiency of studying human papillomavirus infection.

In large active cohort studies of women investigating human papillomavirus (HPV) and cervical neoplasia, many women will be HPV-negative at all time points and testing of all their cervical specimens is an inefficient use of laboratory resources. The aim of this pilot study was to evaluate whether pooling cervical specimens from the same woman might provide a useful pretest of specimens from women unlikely to have high-grade cervical neoplasia or significant HPV exposure. We selected women (n = 187) participating in the Guanacaste Project for whom we already had HPV testing data on all their specimens from multiple visits (median = 8 visits), who were HPV DNA-negative at enrollment and at their 5- to 7-year exit from the cohort, and had no evidence of high-grade cervical neoplasia. Equal aliquots of cervical specimens from these women were pooled to create a proportional pooled specimen. Aliquots of pooled specimens were tested in a masked fashion by MY09/11 L1 consensus primer PCR. Second aliquots of some pooled specimens (n = 83) were included to assess the reliability of pooled testing. Results were compared with the predicted (expected) results based on the obtained test results of the individual specimens collected at interim visits. There was good overall agreement between observed and expected HPV DNA positivity, with a kappa of 0.63 [95% confidence interval (95% CI), 0.51-0.75] and a percent agreement of 83.4% (95% CI, 77.3-88.5%) although the HPV DNA positivity in the pooled specimen was less than expected (P = 0.001). The agreement between observed and expected HPV DNA positivity was related to the number of aliquots pooled, suggesting that positivity was related to viral genome concentrations. The kappa and percent agreement for intra-batch reliability of testing pooled specimens were 0.68 (95% CI, 0.53-0.84) and 84.3% (95% CI, 74.7-91.4%), respectively. We conclude that pooling specimens and testing by PCR may be useful for discriminating HPV DNA-positive from completely negative specimen sets in women who are likely to have been HPV DNA-negative.>

Female↗
PubMed2004

CYP1A1 and GSTM1 polymorphisms in relation to lung cancer risk in Chinese women.

We examined CYP1A1 (I462V) and GSTM1 null polymorphisms in 200 female cases and 144 female controls selected from a population-based case-control study of lung cancer conducted in northeast China, where the rates of lung cancer among Chinese women are especially high. The CYP1A1 codon 462 point mutation in exon 7 (I462V) causes an Ile-Val substitution near the heme binding site. This mutation correlates with inducibility of aryl hydrocarbon hydrolase (AHH) activity, which activates polycyclic aromatic hydrocarbons (PAHs) in tobacco smoke and in indoor air pollution from coal-burning stoves, a risk factor for lung cancer in this study population. We found that the CYP1A1 I462V genotype (combined ile/val and val/val) was significantly associated with lung cancer risk. The odds ratio (OR) was 2.5 (95% confidence interval [CI], 1.55-4.03) after adjustment for significant risk factors such as age, ever smoking status, family history of cancer, and eye irritation when cooking. The association was more pronounced among non-smokers (OR=3.67; 95% CI, 1.85-7.28) than among smokers (OR=1.74, 95% CI, 0.85-3.54). In contrast, we did not find a significant association with the GSTM1 null genotype. In summary, our case-control study of lung cancer among women in northeast China revealed an elevated risk associated with the CYP1A1 I462V genotype, but no interaction with smoking or indoor air pollution was found.

Air Pollution, Indoor↗
PubMed2004

Bias in intervention studies that enroll patients from high-risk clinics.

It is important to evaluate the effects of proposed interventions to reduce the risk of disease among carriers of a highly penetrant mutation, such as the mutations in BRCA1 and BRCA2 for breast and ovarian cancers or in APC and MLH1 or MSH2 for colon cancer. However, some studies that evaluate the effects of interventions designed to reduce risk in mutation carriers may be susceptible to a serious selection bias when they are based in clinics that care for persons at high risk for the disease. A study design in which a large fraction of the case patients were diagnosed before being seen at the clinic and all control subjects are persons previously seen at the clinic can create a false impression of intervention efficacy if, as is likely, mutation carriers seen at the clinic were more likely to receive the intervention than mutation carriers in the general population.

Ambulatory Care Facilities↗
PubMed2004

Case-control study of cancer among US Army veterans exposed to simian virus 40-contaminated adenovirus vaccine.

Simian virus 40 (SV40) was an accidental contaminant of vaccines produced in monkey kidney tissue cultures in the 1950s and early 1960s, including a parenteral adenovirus vaccine given to several hundred thousand US military recruits. Detection of SV40 DNA in tumor tissues by some laboratories suggests that SV40 contributes to human cancers. To determine if entry into US Army service during periods of administration of SV40-contaminated adenovirus vaccine was associated with an increased risk of cancer, the authors conducted a case-control study of cancer occurring in male Army veterans who entered service in 1959-1961. Cases of brain tumors (n = 181), mesothelioma (n = 10), and non-Hodgkin's lymphoma (n = 220) were identified through a Veterans Administration hospital discharge database, as were colon cancer and lung cancer controls (n = 221). Exposure to adenovirus vaccine was assigned on the basis of known periods of adenovirus vaccine administration and dates of Army entry obtained for cancer cases and controls. The odds ratios associated with exposure to SV40-contaminated adenovirus vaccine were 0.81 (95% confidence interval (CI): 0.52, 1.24) for brain tumors, 1.41 (95% CI: 0.39, 5.15) for mesothelioma, and 0.97 (95% CI: 0.65, 1.44) for non-Hodgkin's lymphoma. These findings do not support a role for SV40 in the development of these cancers.

Adenoviridae↗
PubMed2004

A population-based study of vaginal human papillomavirus infection in hysterectomized women.

We compared point prevalences and determinants of human papillomavirus (HPV) DNA detection by testing enrollment vaginal specimens from hysterectomized women (n=569) and enrollment cervical specimens from nonhysterectomized women (n=6098) >or=30 years old, using MY09/MY11 L1 consensus-primer polymerase chain reaction. The subjects were participating in a population-based cohort study (n=10,049) in Guanacaste, Costa Rica, that was initiated in 1993. Non-cancer-associated HPV types, especially types 61, 71, and 72, were detected more frequently in the vaginal specimens from hysterectomized women (23.7% [95% confidence interval [CI], 20.3%-27.4%]) than in the cervical specimens from nonhysterectomized women (16.7% [95% CI, 15.7%-17.6%]) (P=.0001). There was no difference between the prevalences of cancer-associated HPV types in hysterectomized women and those in nonhysterectomized women; in both groups, the prevalence of HPV DNA was greater in women with multiple lifetime sex partners. We infer from our data that the cervical transformation zone may not be needed for cancer-associated HPV infection but may be uniquely susceptible to HPV-induced carcinogenesis; we also infer that specific phylogenetic groups of HPV (i.e., A3/A4/A15) may have a predilection for vaginal epithelium.

Adult↗
PubMed2004

Assessing the probability that a positive report is false: an approach for molecular epidemiology studies.

Too many reports of associations between genetic variants and common cancer sites and other complex diseases are false positives. A major reason for this unfortunate situation is the strategy of declaring statistical significance based on a P value alone, particularly, any P value below.05. The false positive report probability (FPRP), the probability of no true association between a genetic variant and disease given a statistically significant finding, depends not only on the observed P value but also on both the prior probability that the association between the genetic variant and the disease is real and the statistical power of the test. In this commentary, we show how to assess the FPRP and how to use it to decide whether a finding is deserving of attention or "noteworthy." We show how this approach can lead to improvements in the design, analysis, and interpretation of molecular epidemiology studies. Our proposal can help investigators, editors, and readers of research articles to protect themselves from overinterpreting statistically significant findings that are not likely to signify a true association. An FPRP-based criterion for deciding whether to call a finding noteworthy formalizes the process already used informally by investigators--that is, tempering enthusiasm for remarkable study findings with considerations of plausibility.

Analysis of Variance↗
PubMed2004

BRCA1 and sex ratio.

Two recent papers suggest distorted sex and transmission ratios associated with BRCA1 mutations. If real, these would provide novel insights into the normal biological function of this gene and have implications for genetic epidemiologic methods used to estimate penetrance. We addressed these observations in two settings: offspring of 283 mutation carriers and 471 mutation negative subjects from BRCA1/2 mutation-positive families with multiple cases of breast and ovarian cancer (NCI families); and relatives of 115 BRCA1/2 mutation carriers from the Washington Ashkenazi Study (WAS). The male:female ratio was below one in both BRCA1 (0.85, 95% CI 0.7-1.1 in NCI families; 0.90, 95% CI 0.6-1.4 in WAS) and BRCA2 families (0.77, 95% CI 0.5-1.3 and 0.80, 95% CI 0.5-1.2, in the NCI and WAS study groups, respectively). None of the sex ratios deviated significantly from one, and there was no significant difference between BRCA1 and BRCA2 families. The reduced sex ratio was due largely to the offspring of males, a distortion that is probably an artifact of ascertainment biases. Among adult daughters without breast or ovarian cancer born to mutation carriers, as expected, fewer than 50% were mutation carriers (39% in BRCA1 families and 44% in BRCA2 families). It is difficult, due to ascertainment biases, to draw firm conclusions regarding sex ratios in studies of a sex-limited phenotype. Nonetheless, these observations do not support the idea that BRCA1 mutation carriers have a lower ratio of male offspring than BRCA2 mutation carriers.

Breast Neoplasms↗
PubMed2004

Applying new biotechnologies to the study of occupational cancer--a workshop summary.

As high-throughput technologies in genomics, transcriptomics, and proteomics evolve, questions arise about their use in the assessment of occupational cancers. To address these questions, the National Institute for Occupational Safety and Health, the National Cancer Institute, the National Institute of Environmental Health Sciences, and the American Chemistry Council sponsored a workshop 8-9 May 2002 in Washington, DC. The workshop brought together 80 international specialists whose objective was to identify the means for best exploiting new technologies to enhance methods for laboratory investigation, epidemiologic evaluation, risk assessment, and prevention of occupational cancer. The workshop focused on identifying and interpreting markers for early biologic effect and inherited modifiers of risk.

Biomarkers↗
PubMed2003

Quantifying epidemiologic risk factors using non-parametric regression: model selection remains the greatest challenge.

Logistic regression is widely used to estimate relative risks (odds ratios) from case-control studies, but when the study exposure is continuous, standard parametric models may not accurately characterize the exposure-response curve. Semi-parametric generalized linear models provide a useful extension. In these models, the exposure of interest is modelled flexibly using a regression spline or a smoothing spline, while other variables are modelled using conventional methods. When coupled with a model-selection procedure based on minimizing a cross-validation score, this approach provides a non-parametric, objective, and reproducible method to characterize the exposure-response curve by one or several models with a favourable bias-variance trade-off. We applied this approach to case-control data to estimate the dose-response relationship between alcohol consumption and risk of oral cancer among African Americans. We did not find a uniquely 'best' model, but results using linear, cubic, and smoothing splines were consistent: there does not appear to be a risk-free threshold for alcohol consumption vis-à-vis the development of oral cancer. This finding was not apparent using a standard step-function model. In our analysis, the cross-validation curve had a global minimum and also a local minimum. In general, the phenomenon of multiple local minima makes it more difficult to interpret the results, and may present a computational roadblock to non-parametric generalized additive models of multiple continuous exposures. Nonetheless, the semi-parametric approach appears to be a practical advance.

Black or African American↗
PubMed2003

Gynecologic surgeries and risk of ovarian cancer in women with BRCA1 and BRCA2 Ashkenazi founder mutations: an Israeli population-based case-control study.

BACKGROUND: In the general population, the risk of developing ovarian cancer is reduced in women who have undergone tubal ligation, hysterectomy, or oophorectomy, although peritoneal cancer can arise after bilateral oophorectomy. In studies from genetic screening clinics, women with mutations in the breast and ovarian susceptibility genes BRCA1 and BRCA2 have been found to have a low risk of peritoneal carcinoma in the first years after bilateral oophorectomy. We assessed the level and persistence of reduction of ovarian (including peritoneal) cancer risk after gynecologic surgeries for women who carry BRCA1/2 mutations but were not selected from high-risk clinics. METHODS: We identified 1124 Israeli women with incident ovarian cancer or primary peritoneal cancer and tested 847 of them for the three Ashkenazi founder mutations. We compared gynecologic surgery history among all case patients, BRCA1 (n = 187) and BRCA2 (n = 64) carrier case patients, and the non-carrier case patients (n = 598) with that in control subjects drawn from a population registry (n = 2396). We estimated ovarian cancer risk (odds ratios [ORs] with 95% confidence intervals [CIs]) after gynecologic surgery in mutation carriers and non-carriers with logistic regression models. RESULTS: Eight women with primary peritoneal cancer and 128 control subjects reported a previous bilateral oophorectomy (OR = 0.12, 95% CI = 0.06 to 0.24). Other gynecologic surgeries were associated with a 30%-50% reduced risk of ovarian cancer, depending on the type of surgery, with surgery to remove some ovarian tissue associated with the most risk reduction (OR = 0.34, 95% CI = 0.16 to 0.74). Reduced risks were seen in BRCA1/2 carriers and non-carriers. Age at surgery and years since surgery did not affect risk reductions. CONCLUSION: Both BRCA1/2 mutation carriers and non-carriers have reduced risk of ovarian or peritoneal cancer after gynecologic surgery. The magnitude of the reduction depends upon the type and extent of surgery.

Adult↗
PubMed2003

Baseline cytology, human papillomavirus testing, and risk for cervical neoplasia: a 10-year cohort analysis.

BACKGROUND: Annual Pap smear screening has been favored over less frequent screening in the United States to minimize the risk of cervical cancer. We evaluated whether simultaneous screening with a Pap test and human papillomavirus (HPV) testing is useful for assessing the risk for cervical intraepithelial neoplasia (CIN) 3 or cervical cancer. METHODS: We enrolled 23 702 subjects in a study of HPV infection at Kaiser Permanente, Northwest Division, Portland, OR. Data were analyzed for 20 810 volunteers who were at least 16 years old (mean = 35.9 years) with satisfactory baseline Pap tests and suitable samples for HPV testing. Women were followed for up to 122 months (from April 1, 1989, to June 30, 1999) to determine the risk for histopathologically confirmed CIN3 or cancer. RESULTS: Among 171 women with CIN3 or cancer diagnosed over 122 months, 123 (71.9%, 95% confidence interval [CI] = 65.2% to 78.7%) had baseline Pap results of atypical squamous cells or worse and/or a positive HPV test, including 102 (86.4%, 95% CI = 80.3% to 92.6%) of the 118 cases diagnosed within the first 45 months of follow-up. During this 45-month period, the cumulative incidence of CIN3 or cancer was 4.54% (95% CI = 3.61% to 5.46%) among women with a Pap test result of atypical squamous cells or worse, positive HPV tests, or both compared with 0.16% (95% CI = 0.08% to 0.24%) among women with negative Pap and HPV tests. Age, screening behavior, a history of cervical cancer precursors, and a history of treatment for CIN minimally affected results. CONCLUSIONS: Negative baseline Pap and HPV tests were associated with a low risk for CIN3 or cancer in the subsequent 45 months, largely because a negative HPV test was associated with a decreased risk of cervical neoplasia. Negative combined test results should provide added reassurance for lengthening the screening interval among low-risk women, whereas positive results identify a relatively small subgroup that requires more frequent surveillance.

Adolescent↗
PubMed2003

Adjustment for competing risk in kin-cohort estimation.

Kin-cohort design can be used to study the effect of a genetic mutation on the risk of multiple events, using the same study. In this design, the outcome data consist of the event history of the relatives of a sample of genotyped subjects. Existing methods for kin-cohort estimation allow estimation of the risk of one event at a time with the assumption that the censoring events are unrelated to the genetic mutation under study. These methods, however, may produce biased estimates of risk when multiple events are related to the genetic mutation, and follow-up of some of the events may be censored by the onset of other events. Using a competing risk framework to address this problem, we show that cause-specific hazard functions for carriers and noncarriers are identifiable from kin-cohort data. For estimation, we propose an extension of a composite-likelihood approach we described previously. We illustrate the use of the proposed method for estimation of the risk of ovarian cancer from BRCA1/2 mutations in the absence of breast cancer, based on data from the Washington Ashkenazi Kin-Cohort Study. We also evaluate the performance of the proposed estimation method, based on simulated data that were generated following the setup of the Washington Ashkenazi Study.

Age Factors↗
PubMed2003

Chapter 18: Statistical issues in the design and analysis of studies of human papillomavirus and cervical neoplasia.

Appropriately sophisticated statistical approaches are crucial for addressing the increasingly complex set of critical questions that follow from the recognition that human papillomavirus (HPV) is a necessary causal factor for cervical cancer. Cervical cancer researchers have defined the major stages of cervical carcinogenesis, with HPV infection as the necessary cause. Focus of etiologic studies is shifting from establishing causality to determining risk factors for HPV persistence and neoplastic progression using serially collected biomarkers. Prevention-oriented epidemiology and trials of new screening strategies and vaccines will rely on surrogate endpoints because we cannot let women develop cancer when it can be prevented. Future epidemiologic and prevention studies of HPV infection and cervical carcinogenesis will exploit subtle pathologic distinctions and will employ improved measurements of complex molecular biologic phenomena. The anticipated statistical issues are highlighted in this discussion.

Case-Control Studies↗
PubMed2003

Right-sided ectocervical lesions may be associated with false-negative cytology among women with histologic cervical intraepithelial neoplasia 2 or 3.

BACKGROUND: The association between the location of an ectocervical lesion and the sensibility of cytologic screening has not been adequately evaluated. METHODS: We evaluated the proportion of false-negative cytologic interpretations using three independent cytologic interpretations (conventional, PapNet, and ThinPrep) according to lesion location in 111 women with histologic cervical intraepithelial neoplasia 2 or 3 of a population-based study of cervical neoplasia conducted in Guanacaste, Costa Rica. Semiquantitative measures of human papillomavirus viral load were also considered. RESULTS: Lesions on a women's right ectocervix were associated with more frequent false-negative results than lesions on left ectocervix for each of the cytologic methods or when the most severe interpretation was considered (p = .004). Right-sided lesions had nonsignificantly lower viral loads than left-sided lesions (p = .2). CONCLUSIONS: Cervical intraepithelial neoplasia 2 or 3 located on the right side of the cervix may be poorly sampled with broom samplers in some settings, resulting in false-negative cytologic results.

Journal Article↗