345 research outputs found

    The temporal reliability of serum estrogens, progesterone, gonadotropins, SHBG and urinary estrogen and progesterone metabolites in premenopausal women

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    BACKGROUND: There is little existing research to guide researchers in estimating the minimum number of measurement occasions required to obtain reliable estimates of serum estrogens, progesterone, gonadotropins, sex hormone-binding globulin (SHBG), and urinary estrogen and progesterone metabolites in premenopausal women. METHODS: Using data from a longitudinal study of 34 women with a mean age of 42.3 years (SD = 2.6), we calculated the minimum number of measurement occasions required to obtain reliable estimates of 12 analytes (8 in blood, 4 in urine). Five samples were obtained over 1 year: at baseline, and after 1, 3, 6, and 12 months. We also calculated the percent of true variance accounted for by a single measurement and intraclass correlation coefficients (ICC) between measurement occasions. RESULTS: Only 2 of the 12 analytes we examined, SHBG and estrone sulfate (E(1)S), could be adequately estimated by a single measurement using a minimum reliability standard of having the potential to account for 64% of true variance. Other analytes required from 2 to 12 occasions to account for 81% of the true variance, and 2 to 5 occasions to account for 64% of true variance. ICCs ranged from 0.33 for estradiol (E(2)) to 0.88 for SHBG. Percent of true variance accounted for by single measurements ranged from 29% for luteinizing hormone (LH) to 92% for SHBG. CONCLUSIONS: Experimental designs that take the natural variability of these analytes into account by obtaining measurements on a sufficient number of occasions will be rewarded with increased power and accuracy

    The challenge of measuring circulating estradiol at low concentrations

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    Demand for measuring estradiol at low concentrations is increasing, and the widely used 'direct' radioimmunoassays that do not require a preliminary organic purification step may be inadequate in patient care because of their limited accuracy. In observational epidemiology, however, the main concern is to obtain a correct ranking of individuals' hormone concentration relative to the true level (as determined through a 'gold standard'). Despite differences in the absolute scale of measured and true concentrations, correct ranking will permit calculation of unbiased estimates of hormone–disease associations. In prospective studies, the major concerns are the limited volume of often irreplaceable specimens and the need to perform a large number of assays within a reasonable period of time. Organic purification is often not feasible because of sample volume requirements and logistic difficulties, and so the development of accurate, rapid and inexpensive methods to measure sex steroids at low concentrations would represent a valuable new research tool for both clinicians and epidemiologists

    Prediagnostic sex steroid hormones in relation to male breast cancer risk

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    Purpose Although previous studies have implicated a variety of hormone-related risk factors in the etiology of male breast cancers, no previous studies have examined the effects of endogenous hormones. Patients and Methods Within the Male Breast Cancer Pooling Project, an international consortium comprising 21 case-control and cohort investigations, a subset of seven prospective cohort studies were able to contribute prediagnostic serum or plasma samples for hormone quantitation. Using a nested case-control design, multivariable unconditional logistic regression analyses estimated odds ratios and 95% CIs for associations between male breast cancer risk and 11 individual estrogens and androgens, as well as selected ratios of these analytes. Results Data from 101 cases and 217 matched controls were analyzed. After adjustment for age and date of blood draw, race, and body mass index, androgens were found to be largely unrelated to risk, but circulating estradiol levels showed a significant association. Men in the highest quartile had an odds ratio of 2.47 (95% CI, 1.10 to 5.58) compared with those in the lowest quartile (trend P = .06). Assessment of estradiol as a ratio to various individual androgens or sum of androgens showed no further enhancement of risk. These relations were not significantly modified by either age or body mass index, although estradiol was slightly more strongly related to breast cancers occurring among younger (age < 67 years) than older men. Conclusion Our results support the notion of an important role for estradiol in the etiology of male breast cancers, similar to female breast cancers

    Prospective associations of circulating bile acids and short-chain fatty acids with incident colorectal cancer

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    Background Human studies investigating the prospective relationship between microbial metabolites and colorectal cancer (CRC) risk are lacking. We tested whether higher serum bile acids (BAs) and lower short-chain fatty acids (SCFAs) were associated with CRC risk. Methods In baseline serum collected more than 30 years before a CRC diagnosis, we quantified concentrations of 15 BAs and 6 SCFAs using targeted liquid chromatography with tandem mass spectrometry assays in 1:1 matched cases and controls from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial (men: n = 262 cases; women: n = 233 cases) and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (men: n = 598 cases). We estimated odds ratios (ORs) and 95% confidence intervals (CIs) for BA and SCFA quartiles and summary measures with CRC overall and by anatomic location using multivariable conditional logistic regression models. PLCO analyses were stratified by sex. All statistical tests were 2-sided. Results In PLCO women, 7 BAs were strongly associated with increased CRC risk, including the secondary BAs, deoxycholic (ORQ4 v Q1 = 2.85, 95% CI = 1.45 to 5.60, Qtrend = 0.011), glycodeoxycholic (OR Q4 v Q1 = 3.45, 95% CI = 1.79 to 6.64, Qtrend = 0.006), taurodeoxycholic (OR Q4 v Q1 = 2.36, 95% CI = 1.22 to 4.55, Qtrend = 0.023), and glycolithocholic acid (ORQ4 v Q1 = 2.71, 95% CI = 1.41 to 5.22, Qtrend = 0.015). Women in the highest compared with lowest quartile of total SCFAs had a 45% lower risk of CRC (OR = 0.55, 95% CI = 0.31 to 0.98, Ptrend = .03). Associations for total BAs and SCFAs were strongest among women with proximal colon cancer. No statistically significant associations were observed for BA or SCFA measures among men. Conclusions Serum concentrations of BAs, particularly downstream microbial metabolites of cholic acid, were strongly associated with increased risk of CRC among women

    Cessation of smoking and drinking and the risk of laryngeal cancer

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    A case–control study was conducted in Italy and Switzerland between 1992 and 2000 on 527 cases of laryngeal cancer and 1297 hospital controls. The risk of laryngeal cancer steadily decreased from 3 years after stopping smoking. Some decline in risk was observed only 20 years or more after stopping drinking

    Relation of Serum Estrogen Metabolites with Terminal Duct Lobular Unit Involution Among Women Undergoing Diagnostic Image-Guided Breast Biopsy

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    Higher levels of circulating estrogens and estrogen metabolites (EMs) have been associated with higher breast cancer risk. In breast tissues, reduced levels of terminal duct lobular unit (TDLU) involution, as reflected by higher numbers of TDLUs and acini per TDLU, have also been linked to elevated breast cancer risk. However, it is unknown whether reduced TDLU involution mediates the risk associated with circulating EMs. In a cross-sectional analysis of 94 premenopausal and 92 postmenopausal women referred for clinical breast biopsy at an academic facility in Vermont, we examined the associations of 15 EMs, quantified using liquid chromatography-tandem mass spectrometry, with the number of TDLUs and acini count/TDLU using zero-inflated Poisson regression with a robust variance estimator and ordinal logistic regression models, respectively. All analyses were stratified by menopausal status and adjusted for potential confounders. Among premenopausal women, comparing the highest vs. the lowest tertiles, levels of unconjugated estradiol (risk ratio (RR) = 1.74, 95 % confidence interval (CI) = 1.06-2.87, p trend = 0.03), 2-hydroxyestrone (RR = 1.74, 95 % CI = 1.01-3.01, p trend = 0.04), and 4-hydroxyestrone (RR = 1.74, 95 % CI = 0.99-3.06, p trend = 0.04) were associated with significantly higher TDLU count. Among postmenopausal women, higher levels of estradiol (RR = 2.09, 95 % CI = 1.01-4.30, p trend = 0.04) and 16α-hydroxyestrone (RR = 2.27, 95 % CI = 1.29-3.99, p trend = 0.02) were significantly associated with higher TDLU count. Among postmenopausal women, higher levels of EMs, specifically conjugated estrone and 2- and 4-pathway catechols, were also associated with higher acini count/TDLU. Our data suggest that higher levels of serum EMs are generally associated with lower levels of TDLU involution

    Relationship between crown-like structures and sex-steroid hormones in breast adipose tissue and serum among postmenopausal breast cancer patients

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    Abstract Background Postmenopausal obesity is associated with increased circulating levels of androgens and estrogens and elevated breast cancer risk. Crown-like structures (CLS; microscopic foci of dying adipocytes surrounded by macrophages) are proposed to represent sites of increased aromatization of androgens to estrogens. Accordingly, we examined relationships between CLS and sex-steroid hormones in breast adipose tissue and serum from postmenopausal breast cancer patients. Methods Formalin-fixed paraffin embedded benign breast tissues collected for research from postmenopausal women ( n \u2009=\u200983) diagnosed with invasive breast cancer in the Polish Breast Cancer Study (PBCS) were evaluated. Tissues were immunohistochemically stained for CD68 to determine the presence of CLS per unit area of adipose tissue. Relationships were assessed between CD68 density and CLS and previously reported sex-steroid hormones quantified using radioimmunoassays in serum taken at the time of diagnosis and in fresh frozen adipose tissue taken at the time of surgery. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the relationships between hormones (in tertiles) and CLS. Results CLS were observed in 36% of benign breast tissues, with a higher frequency among obese versus lean women (54% versus 17%, p \u2009=\u20090.03). Detection of CLS was not related to individual hormone levels or breast tumor pathology characteristics. However, detection of CLS was associated with hormone ratios. Compared with women in the highest tertile of estrone:androstenedione ratio in fat, those in the lowest tertile were less likely to have CLS (OR 0.12, 95% CI 0.03\u20130.59). A similar pattern was observed with estradiol:testosterone ratio in serum and CLS (lowest versus highest tertile, OR 0.18, 95% CI 0.04\u20130.72). Conclusions CLS were more frequently identified in the breast fat of obese women and were associated with increased ..

    Expression and prognostic value of circulating angiogenic cytokines in pancreatic cancer

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    <p>Abstract</p> <p>Background</p> <p>The utility of circulating angiogenic cytokines (CAC) as biomarkers in pancreatic cancer has not been clarified yet. We investigated the expression and prognostic associations of seven CAC in patients with pancreatic cancer.</p> <p>Methods</p> <p>Serum samples were collected preoperatively in patients undergoing surgery for localized pancreatic cancer (n = 74), metastatic pancreatic cancer (n = 24) or chronic pancreatitis (n = 20) and in healthy controls (n = 48). Quantitative enzyme-linked immunosorbent assays and multiplex protein arrays were used to determine circulating levels of VEGF, VEGFR-1, PlGF, PDGF-AA, PDGF-BB, Ang-1 and EGF. Multivariate analyses on cancer-specific survival were performed with a Cox proportional hazards model.</p> <p>Results</p> <p>VEGF (p < 0.0001), PDGF-AA (p < 0.0001), Ang-1 (p = 0.002) and EGF (p < 0.0001) were differentially expressed in patients with pancreatic cancer compared to healthy controls. The presence of lymph node metastases was associated with increased levels of all CAC except for PlGF, whereas there were only minor associations of CAC with other clinicopathologic variables. The multivariate model including the entire angiogenic panel revealed high levels of circulating PDGF-AA (hazard ratio 4.58; 95% confidence interval 1.43 - 14.69) as predictor of poor cancer-specific survival, whereas high levels of PDGF-BB (0.15; 0.15 - 0.88), Ang-1 (0.30; 0.10 - 0.93) and VEGF (0.24; 0.09 - 0.57) were associated with a favorable prognosis.</p> <p>Conclusion</p> <p>Circulating levels of certain angiogenic cytokines correlate with patients' prognosis after resection for pancreatic cancer, if a panel of several CAC is considered simultaneously. These data should be considered in future studies evaluating angiogenic factors as prognostic biomarkers and therapeutic targets in patients with pancreatic cancer.</p

    Biologic markers of risk in nipple aspirate fluid are associated with residual cancer and tumour size

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    We previously demonstrated that nipple aspirate fluid (NAF) can be obtained from virtually all non-Asian women between the ages of 30 and 72. The focus of this report is to (1) determine the association of candidate markers of breast cancer risk in NAF obtained from fresh mastectomy specimens with residual breast carcinoma, and (2) evaluate the association of the markers with breast tumour progression. Nipple aspiration was performed on 97 specimens. Cytology, DNA index (including % hypertetraploid cells), cell cycle parameters (S phase fraction, % cells in G2/M), prostate-specific antigen (PSA), epidermal growth factor (EGF), testosterone, carcinoembryonic antigen (CEA) and prostaglandin D synthase (PGDS) were evaluated in NAF for their association with (1) residual ductal carcinoma in situ (DCIS) or invasive cancer, and (2) pathologic tumour size. NAF was obtained from 99% (96/97) of specimens. Atypical and malignant NAF cytology were significantly associated with residual DCIS or invasive cancer (P = 0.001) and with larger tumours (P = 0.004). One hundred per cent and 88% of subjects with malignant and atypical NAF cytology, respectively, had residual carcinoma. The percentage of cells in G2/M and DNA index were associated both with risk of residual carcinoma (P = 0.01 for each) and larger tumour size (DNA index, P = 0.03; G2/M, P = 0.05), although neither biomarker improved the ability of NAF cytology, to predict residual breast cancer. Higher DNA index was associated with atypical cytology (P = 0.0001). In summary, atypical and malignant NAF cytology are associated with larger tumour size, and are highly predictive of residual carcinoma after needle or excisional biopsy of the breast. © 1999 Cancer Research Campaig
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