Faculty Bibliography

Background: Reproductive and hormonal factors are involved in the etiology of breast cancer, but there are only a few prospective studies on endogenous sex hormone levels and breast cancer risk. We reanalyzed the worldwide data from prospective studies to examine the relationship between the levels of endogenous sex hormones and breast cancer risk in postmenopausal women. Methods: We analyzed the individual data from nine prospective studies on 663 women who developed breast cancer and 1765 women who did not. None of the women was taking exogenous sex hormones when their blood was collected to determine hormone levels. The relative risks (RRs) for breast cancer associated with increasing hormone concentrations were estimated by conditional logistic regression on case-control sets matched within each study. Linear trends and heterogeneity of RRs were assessed by two-sided tests or chi-square tests, as appropriate. Results: The risk for breast cancer increased statistically significantly with increasing concentrations of all sex hormones examined: total estradiol, free estradiol, non-sex hormone-binding globulin (SHBG)-bound estradiol (which comprises free and albumin-bound estradiol), estrone, estrone sulfate, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and testosterone. The RRs for women with increasing quintiles of estradiol concentrations, relative to the lowest quintile, were 1.42 (95% confidence interval [CI] = 1.04 to 1.95), 1.21 (95% CI = 0.89 to 1.66), 1.80 (95% CI = 1.33 to 2.43), and 2.00 (95% CI = 1.47 to 2.71; Ptrend<.001); the RRs for women with increasing quintiles of free estradiol were 1.38 (95% CI = 0.94 to 2.03), 1.84 (95% CI = 1.24 to 2.74), 2.24 (95% CI = 1.53 to 3.27), and 2.58 (95% CI = 1.76 to 3.78; Ptrend<.001). The magnitudes of risk associated with the other estrogens and with the androgens were similar. SHBG was associated with a decrease in breast cancer risk (Ptrend = .041). The increases in risk associated with increased levels of all sex hormones remained after subjects who were diagnosed with breast cancer within 2 years of blood collection were excluded from the analysis. Conclusion: Levels of endogenous sex hormones are strongly associated with breast cancer risk in postmenopausal women

BACKGROUND: More than 20 studies have investigated the relation between meat and dairy food consumption and breast cancer risk with conflicting results. Our objective was to evaluate the risk of breast cancer associated with meat and dairy food consumption and to assess whether non-dietary risk factors modify the relation. METHODS: We combined the primary data from eight prospective cohort studies from North America and Western Europe with at least 200 incident breast cancer cases, assessment of usual food and nutrient intakes, and a validation study of the dietary assessment instrument. The pooled database included 351,041 women, 7379 of whom were diagnosed with invasive breast cancer during up to 15 years of follow-up. RESULTS: We found no significant association between intakes of total meat, red meat, white meat, total dairy fluids, or total dairy solids and breast cancer risk. Categorical analyses suggested a J-shaped association for egg consumption where, compared to women who did not eat eggs, breast cancer risk was slightly decreased among women who consumed < 2 eggs per week but slightly increased among women who consumed > or = 1 egg per day. CONCLUSIONS: We found no significant associations between intake of meat or dairy products and risk of breast cancer. An inconsistent relation between egg consumption and risk of breast cancer merits further investigation

Background. More than 20 studies have investigated the relation between meat and dairy consumption and breast cancer risk with conflicting results. Our objective was evaluate the risk of assess whether non-dietary risk factors modify the relation. studies from North America and Western Europe with at least 200 intakes, and a validation study of dietary assessment instrument. diagnosed with invasive breast cancer during to 15 year of intakes of total meat, red me white meat, total dairy fluids, or total dairy solids and breast cancer risk. Categor analyses suggested a J-shaped association for egg consumption where, comp to women who did not eat eggs, breast cancer risk was slightly decreased am women who consumed <2 eggs per week but slightly increased among women who consumed >=1 egg per day. Conclusions. We produ and risk of breast cancer. An inconsistent relation between egg consumption risk of breast cancer merits further investigation

BACKGROUND: Epidemiological evidence suggests that chronic inflammation may influence ovarian carcinogenesis. The study objective was to examine the association between the commonly used anti-inflammatory drug aspirin and epithelial ovarian cancer. METHODS: The authors conducted a case-control study based in the New York University Women's Health Study cohort enrolled between 1985 and 1991 in New York City. After a median follow-up period of 12 years, 68 incident cases of epithelial ovarian cancer were identified. Data about regular aspirin use were collected during the 1994-1996 follow-up questionnaire. Using a case-control study design, 10 controls per case were randomly selected among study participants who matched the case by age and menopausal status. Conditional logistic regression analysis was used to study the relationships between aspirin and epithelial ovarian cancer by generating odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Relative to no aspirin use, the OR for epithelial ovarian cancer among women who reported aspirin use three or more times per week for a period of at least 6 months was 0.60 (95% CI 0.26, 1.38), after adjustment for age at menarche, parity, oral contraceptive use, and first-degree family history of breast cancer before age 50. Among recent, within the previous 5 years, users of aspirin, the adjusted OR was 0.36 (95% CI 0.11, 1.18). CONCLUSION: Although confidence intervals included unity, the observed risk estimates seem to be compatible with previous studies suggesting that regular aspirin use could be inversely associated with risk of epithelial ovarian cancer

Evidence is accumulating that elevated circulating insulin-like growth factor I (IGF-I) is related to increased cancer risk. The identification of hormonal, reproductive and lifestyle characteristics influencing its synthesis and bioavailability is of particular interest. Data from 400 women, who served as controls in two case-control studies nested within the same prospective cohort study, were combined. IGF-I, IGF-binding proteins 1, 2 and 3 (IGFBP-1, -2, -3) and insulin were measured in serum samples from all subjects and cotinine in 186 samples. Age appears to be the most important determinant of total IGF-I levels in women. Anthropometric measures, such as body mass index (BMI) or waist-to-hip ratio (WHR) do not seem to influence total IGF-I concentrations in peripheral blood, but may modulate IGF-I bioavailability through insulin-dependent changes in IGFBP-1 and -2 concentrations. Age at menarche, phase of the menstrual cycle at blood draw, parity, menopause, past oral contraceptive or hormone replacement therapy use, and tobacco smoking do not appear to exert an independent effect on IGF-I and its binding proteins. There was some suggestion that regular physical activity may increase total IGF-I and that women with positive family history of breast cancer might have higher IGF-I levels than those without such diagnosis in their relatives

Endometrial carcinoma is the most common cancer of the female reproductive organs in the United States. International comparisons reveal that the incidence of endometrial cancer vary widely between different countries with the highest rates observed in North America and Northern Europe, intermediate rates in Eastern Europe and Latin America, and lowest rates in Asia and Africa. International variation in endometrial cancer rates may represent differences in the distribution of known risk factors, which include obesity, postmenopausal estrogen replacement, ovarian dysfunction, diabetes mellitus, infertility, nulliparity, and tamoxifen use. Most of the risk factors for endometrial cancer can be explained within the framework of the unopposed estrogen hypothesis, which proposes that exposure to estrogens unopposed by progesterone or synthetic progestins leads to increased mitotic activity of endometrial cells, increased number of DNA replication errors, and somatic mutations resulting in malignant phenotype. Although the impact of exogenous hormone replacement was intensively studied during the last two decades, less is known about the effects of endogenous hormones in endometrial cancer. A review of available experimental, clinical, and epidemiologic data suggests that in addition to estrogens, other endogenous hormones, including progesterone, androgens, gonadotropins, prolactin, insulin, and insulin-like growth factors, may play a role in the pathogenesis of different histopathologic types of endometrial cancer

The search for new prognostic indicators is especially important in the diagnosis and treatment of ovarian cancer because clinicopathologic criteria currently used to predict survival are largely inadequate. We examined 2 groups of patients with epithelial ovarian cancer, 1 group of long-term survivors (>5 years), and 1 group of short-term survivors (<2 years) for levels of expression of the cell cycle regulators p57(KIP2), cyclin D1, and cyclin E and their relationship with survival. Our findings show that p57(KIP2) is not associated with prognosis, in contrast to p27(KIP1) expression, which is previously shown to be positively associated with long-term survival in univariate analysis (P =.001). Cyclin E expression, in contrast to cyclin D1 expression, is marginally associated with short-term survival in univariate analysis for a group of 53 women. Among the short-term survivors, 15 (65%) of 23 were positive for cyclin E expression, compared with only 11 (37%) of 30 long-term survivors (P = 0.054). This association remained significant (P =.04) in a logistic regression analysis adjusted simultaneously for performance status and extent of residual disease, the 2 strongest predictors of survival in our study. We also found a significant difference in the frequency of the cyclin E staining pattern between nonserous and serous ovarian tumor subtypes (P =.0002). Immunostaining for levels of cyclin E and p27(KIP1) expression may have potential as prognostic markers in the management of ovarian cancer

The gonadotropin hypothesis postulates that excessive gonadotropin stimulation results in increased proliferation and subsequent malignant transformation of ovarian epithelium. The authors evaluated this hypothesis by analyzing the association between serum levels of wild-type luteinizing hormone (LH) and ovarian cancer risk. They also examined the relation between a variant of LH containing two missense point mutations (Trp(8)Arg and Ile(15)Thr) in its beta-subunit and ovarian cancer risk. Fifty-eight cases of epithelial ovarian cancer and 116 controls matched on age, menopausal status, and date of blood donation were included in a case-control study nested within the New York University Women's Health Study, a prospective cohort enrolled between 1985 and 1991 in New York City. Wild-type serum levels and variant LH status were determined by immunofluorometric assays in which monoclonal antibodies specific for wild-type and variant LH were used. Compared with women in the lowest tertile of wild-type LH, women in the highest tertile had a lower risk of ovarian cancer, after adjustment for potential confounders (odds ratio = 0.42, 95% confidence interval: 0.09, 2.09). Women heterozygous for variant LH were not at increased risk (adjusted odds ratio = 0.95, 95% confidence interval: 0.27, 3.34). The results suggest that neither wild-type LH levels nor variant LH status is associated with increased risk of epithelial ovarian cancer