Analysis of gene expression data suggests that breast cancers are divisible into molecular subtypes which have distinct clinical features. This study evaluates whether pathologic features and etiologic associations differ among molecular subtypes. We evaluated 804 women with invasive breast cancers and 2,502 controls participating in a Polish Breast Cancer Study. Immunohistochemical stains for estrogen receptor A, progesterone receptor, human epidermal growth factor receptors (HER2 and HER1), and cytokeratin 5 were used to classify cases into five molecular subtypes: luminal A, luminal B, HER2-expresing, basal-like, and unclassified. Relative risks were estimated using adjusted odds ratios and 95% confidence intervals. We observed that compared with the predominant luminal A tumors (69%), other subtypes were associated with unfavorable clinical features at diagnosis, especially HER2-expressing (8%) and basal-like (12%) tumors. Increasing body mass index significantly reduced the risk of luminal A tumors among premenopausal women (odds ratios, 0.71; 95% confidence intervals, 0.57-0.88 per fiveunit increase), whereas it did not reduce risk for basal-like tumors (1.18; 0.86-1.64; P heterogeneity = 0.003). On the other hand, reduced risk associated with increasing age at menarche was stronger for basal-like (0.78; 0.68-0.89 per 2-year increase) than luminal A tumors (0.90; 0.95-1.08; P heterogeneity = 0.0009). Although family history increased risk for all subtypes (except for unclassified tumors), the magnitude of the relative risk was highest for basal-like tumors. Results from this study have shown that breast cancer risk factors may vary by molecular subtypes identified in expression studies, suggesting etiologic, in addition to clinical, heterogeneity of breast cancer. (Cancer Epidemiol Biomarkers Prev 2007;16(3):439 -43)

Evidence suggests that breast cancer hormone receptor status varies by etiologic factors, but studies have been inconsistent. In a population-based case-control study in Poland that included 2,386 cases and 2,502 controls, we assessed ER-a and PR status of tumors based on clinical records according to etiologic exposure data collected via interview. For 842 cancers, we evaluated ER-a, ER-b, PR and HER2 levels by semiquantitative microscopic scoring of immunostained tissue microarrays and a quantitative immunofluorescence method, automated quantitative analysis (AQUA TM ). We related marker levels in tumors to etiologic factors, using standard regression models and novel statistical methods, permitting adjustment for both correlated tumor features and exposures. Results obtained with different assays were generally consistent. Receptor levels varied most significantly with body mass index (BMI), a factor that was inversely related to risk among premenopausal women and directly related to risk among postmenopausal women with larger tumors. After adjustment for correlated markers, exposures and pathologic characteristics, PR and HER2 AQUA levels were inversely related to BMI among premenopausal women ( p-trend 5 0.01, both comparisons), whereas among postmenopausal women, PR levels were associated directly with BMI ( p-trend 5 0.002). Among postmenopausal women, analyses demonstrated that BMI was related to an interaction of PR and HER2: odds ratio (OR) 5 0.86 (95% CI 5 0.69-1.07) for low PR and HER2 expression vs. OR 5 1.78 (95% CI 5 1.25-2.55) for high expression (p-heterogeneity 5 0.001). PR and HER2 levels in breast cancer vary by BMI, suggesting a heterogeneous etiology for tumors related to these markers. ' 2007 Wiley-Liss, Inc.Key words: breast; etiology; hormones; epidemiology Amassing data suggest that breast cancers are characterized by ''molecular portraits'' that are established at inception, remain stable over time and represent critical determinants of tumor biology.1 Hormone receptor status is a key parameter in molecular classifications of breast cancer, 2,3 which serves as a marker of hormone-dependent growth and predictor of responsiveness to hormonal treatments. Consequently, researchers have hypothesized that etiologic factors mediated by hormones might be more strongly associated with breast cancers that express hormone receptors when compared with those that are receptor-negative. 4,5 A recent literature review found evidence that nulliparity, late age at first birth and postmenopausal obesity are associated with greater risk for estrogen receptor-a (ER-a)-positive cancers when compared with ER-a-negative tumors, and that early menarche was more strongly linked to tumors coexpressing ER-a and progesterone receptor (PR). 4 Subsequently, a metaanalysis updating this review affirmed the heterogeneous associations for nulliparity and late age at first birth, but not for age at menarche. 5 However, results of studies have not been entirely consistent, especially when limited by small sample sizes,...

We evaluated the immunocytochemical (ICC) expression of K homology domain containing protein overexpressed in cancer (KOC) in pancreatic endoscopic ultrasound-guided fine needle aspirates (EUS-FNAs) to assess its potential use as an adjunct in differentiating nonneoplastic (GI epithelium) and benign neoplastic epithelia (benign epithelial pancreatic neoplasms) from pancreatic adenocarcinoma cells. Forty-eight cases of EUS-FNAs with histological and/or clinical follow-up data were selected for this study. Alcohol-fixed and PAP-stained slides were stained with monoclonal antibody to KOC/L523S (clone 69.1). Results were recorded as negative or positive. KOC expression was present in 35/40 (88%) of adenocarcinomas (Ac) and was negative in all eight benign cases. The sensitivity and specificity were as follows: cytology 85 and 100%, KOC 88 and 100%; combination of cytology and KOC 95 and 100%. We conclude that KOC ICC expression on alcohol-fixed smears along with cytology improves the sensitivity of EUS-FNAs in the diagnosis of pancreatic Ac, and KOC reactivity is especially useful in differentiating Ac from nonneoplastic gastrointestinal epithelium and benign neoplastic epithelia.

The objective of this study was to evaluate the coexpression patterns of hormonal markers in breast cancer tissue and their relationship with pathologic characteristics and epidemiologic risk factors. We evaluated the expression of 17 markers by immunohistochemistry in 842 invasive breast carcinomas collected in a population-based case-control study conducted in Poland. Based on marker correlations, factor analysis identified four major coexpression patterns ( factors): ''nuclear receptor factor'' [estrogen receptor (ER)-A, progesterone receptor, androgen receptor, cyclin D1, and aromatase], ''estrogen metabolism/ER-B factor'' (ER-B, peroxisome proliferator-activated receptor-;, steroid sulfatase, estrogen sulfonotransferase, and cytochrome P450 1B1), ''HER2 factor'' (human epidermal growth factor receptor 2, E-cadherin, cyclooxygenase-2, aromatase, steroid sulfatase), and ''proliferation factor'' (cytokeratin 5, cytokeratin 5/6, epidermal growth factor receptor, P53). Three of these factors corresponded to molecular subtypes previously defined by expression profiling; however, the estrogen metabolism/ER-B factor seemed to be distinctive. High scores for this factor were associated with high tumor grade (P heterogeneity = 0.02), younger age at menarche (P heterogeneity = 0.04), lower current body mass index among premenopausal women (P heterogeneity = 0.01), and older age at menopause (P heterogeneity = 0.04). High scores for the proliferation factor were also associated with early menarche (P heterogeneity < 0.0001), and in contrast to the estrogen metabolism/ ER-B factor, higher current body mass index among premenopausal women (P heterogeneity = 0.03). Our analysis of hormonal pathway markers independently confirmed several previously defined molecular subtypes identified by gene expression profiling and augmented these findings by suggesting the existence of additional relationships related to ER-B and enzymes involved in hormone metabolism. [Cancer Res 2007;67(21):10608-17]

Biliary tract brush cytology is one of the favored methods of evaluating lesions of the pancreatobiliary tract. However, although its specificity has been reported to be high (91-100%), the sensitivity is lower (30-88%). In this study we applied KOC and S100A4 protein immunocytochemistry to assess their potential use as adjunct markers in differentiating benign from malignant cells, and improve the diagnostic sensitivity of this method for pancreatobiliary malignancies. The authors examined KOC and S100A4 protein expression in 44 alcohol-fixed cytology specimens obtained by biliary brushings. Diagnoses included: (1) benign/atypical favor reactive (20 cases), (2) atypical/not diagnostic of malignancy (3 cases), and (3) suspicious for malignancy/malignant (21 cases). Alcohol-fixed Papanicolaou-stained slides (PAP) were stained with monoclonal antibody to KOC/L523S and polyclonal antibody to S100A4 protein. Results were recorded as negative or positive. Twenty-four cases were confirmed positive for adenocarcinoma and 20 cases were negative. The sensitivity and specificity of cytology was 83 and 95%, KOC showed a sensitivity of 92% and specificity of 95%. S100A4 protein showed a sensitivity of 79% and a specificity of 95%. The combined use of KOC and S100A4 protein showed a sensitivity of 100% and a specificity of 95%, respectively. The concurrent use of KOC and S100A4 protein improves the diagnostic sensitivity of biliary brushings cytology and demonstrates similar specificity as cytology alone in the diagnosis of pancreatobiliary malignancy.