Susanne Haas

Risk of estrogen receptor-positive and -negative breast cancer and single-nucleotide polymorphism 2q35-rs13387042

BACKGROUND A recent genome-wide association study identified single-nucleotide polymorphism (SNP) 2q35-rs13387042 as a marker of susceptibility to estrogen receptor (ER)-positive breast cancer. We attempted to confirm this association using the Breast Cancer Association Consortium. METHODS 2q35-rs13387042 SNP was genotyped for 31 510 women with invasive breast cancer, 1101 women with ductal carcinoma in situ, and 35 969 female control subjects from 25 studies. Odds ratios (ORs) were estimated by logistic regression, adjusted for study. Heterogeneity in odds ratios by each of age, ethnicity, and study was assessed by fitting interaction terms. Heterogeneity by each of invasiveness, family history, bilaterality, and hormone receptor status was assessed by subclassifying case patients and applying polytomous logistic regression. All statistical tests were two-sided. RESULTS We found strong evidence of association between rs13387042 and breast cancer in white women of European origin (per-allele OR = 1.12, 95% confidence interval [CI] = 1.09 to 1.15; P(trend) = 1.0 x 10(-19)). The odds ratio was lower than that previously reported (P = .02) and did not vary by age or ethnicity (all P > or = .2). However, it was higher when the analysis was restricted to case patients who were selected for a strong family history (P = .02). An association was observed for both ER-positive (OR = 1.14, 95% CI = 1.10 to 1.17; P = 10(-15)) and ER-negative disease (OR = 1.10, 95% CI = 1.04 to 1.15; P = .0003) and both progesterone receptor (PR)-positive (OR = 1.15, 95% CI = 1.11 to 1.19; P = 5 x 10(-14)) and PR-negative disease (OR = 1.10, 95% CI = 1.06 to 1.15; P = .00002). CONCLUSION The rs13387042 is associated with both ER-positive and ER-negative breast cancer in European women.

Expression of xenobiotic and steroid hormone metabolizing enzymes in human breast carcinomas

The potential to metabolize endogenous and exogenous substances may influence breast cancer development and tumor growth. Therefore, the authors investigated the protein expression of Glutathione S‐transferase (GST) isoforms and cytochrome P450 (CYP) known to be involved in the metabolism of steroid hormones and endogenous as well as exogenous carcinogens in breast cancer tissue to obtain new information on their possible role in tumor progression. Expression of GST pi, mu, alpha and CYP1A1/2, 1A2, 3A4/5, 1B1, 2E1 was assessed by immunohistochemistry for primary breast carcinomas of 393 patients from the German GENICA breast cancer collection. The percentages of positive tumors were 50.1 and 44.5% for GST mu and CYP2E1, and ranged from 13 to 24.7% for CYP1A2, GST pi, CYP1A1/2, CYP3A4/5, CYP1B1. GST alpha was expressed in 1.8% of tumors. The authors observed the following associations between strong protein expression and histopathological characteristics: GST expression was associated with a better tumor differentiation (GST mu, p = 0.018) and with reduced lymph node metastasis (GST pi, p = 0.02). In addition, GST mu expression was associated with a positive estrogen receptor and progesterone receptor status (p < 0.001). CYP3A4/5 expression was associated with a positive nodal status (p = 0.018). Expression of CYP1B1 was associated with poor tumor differentiation (p = 0.049). Our results demonstrate that the majority of breast carcinomas expressed xenobiotic and drug metabolizing enzymes. They particularly suggest that GST mu and pi expression may indicate a better prognosis and that strong CYP3A4/5 and CYP1B1 expression may be key features of nonfavourable prognosis.

Investigation of Genetic Variants of Genes of the Hemochromatosis Pathway and Their Role in Breast Cancer

Iron overload has been noticed as a feature of human breast cancer. Cellular iron uptake is regulated by the hemochromatosis and transferrin receptor system, mutations of which cause the iron storage disease hereditary hemochromatosis. To understand the role of hemochromatosis and transferrin receptor system mutations in breast cancer, we analyzed 19 sequence variations at HFE, TFR1, TFR2, and FPN1 and compared genotype frequencies between cases and controls in a German population. There were 688 breast cancer patients and 724 population-based and age-matched controls. For genotyping, we applied the Hemochromatosis Strip Assay and TaqMan allelic discrimination analyses. In addition to genotype frequencies, we established frequencies of compound genotypes. The frequencies of HFE at His63Asp, Ser65Cys, and Cys282Tyr, and of TFR1 at Ser142Gly minor alleles in this German population were 15.9%, 1.8%, 5.6%, and 46.0%, respectively. No rare variants at 15 more loci at HFE, TFR2, and FPN1 were observed in breast cancer patients. There were no significant differences of allele and genotype frequencies between cases and controls. Triple and quadruple compound genotypes at HFE_His63_Cys282-TFR1_Ser142Gly and HFE_His63_Ser65_Cys282-TFR1_Ser142Gly showed a nonsignificant increase in cases. Although limited by low numbers, an increased prevalence of the HFE Tyr282 minor allele was observed in breast cancer cases with a high number of affected lymph nodes (P = 0.032). Our data suggest that variants of the hemochromatosis-transferrin receptor system have no direct effect on the incidence of breast cancer in Germany. Possible effects on tumor progression and prognosis remain elusive.

Common variants in the UBC9 gene encoding the SUMO-conjugating enzyme are associated with breast tumor grade

UBC9 encodes a protein that conjugates small ubiquitin‐related modifier (SUMO) to target proteins resulting in a change of their localization, activity or stability. Genetic variability may affect expression and activity of UBC9 and may have an impact on breast tumor progression. We investigated associations between UBC9 genotypes and histopathological parameters in 1,021 breast cancer cases of the GENICA collection using a single nucleotide polymorphism (SNP) tagging approach. Genotyping analyses were performed by TaqMan® allelic discrimination. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by ordinal logistic regression. Multiple imputation based on HapMap data was applied to boost the power of the study. The study revealed significant associations of three UBC9 SNPs with histological grade (rs7187167, ptrend = 0.001; rs11248866, ptrend = 0.009; rs8052688, ptrend = 0.008). Model selection identified a recessive penetrance model for rs7187167 as the best representation of tumor grade (global p = 0.001). This model did not improve by inclusion of additional SNPs in linkage disequilibrium. Imputation of SNPs in a 300 kb region around the genotyped SNPs supported rs7187167 as a major contributor to tumor grade. Compared with common allele carriers, rare homozygotes presented less frequently with high grade tumors (G3 vs. G1: OR 0.26, 95% CI 0.11–0.62; G3 vs. G2: OR 0.45, 95% CI 0.23–0.86). In addition to tumor size, nodal status and estrogen receptor status, multivariate analyses confirmed an independent role of rs7187167 as predictor of tumor grade (p = 0.0003). The present results underline the value of genetic variation in UBC9 for breast cancer prognosis.

A Novel Polymorphism in the Promoter Region of ERBB4 Is Associated with Breast and Colorectal Cancer Risk

Purpose: The receptor tyrosine kinase ERBB4/HER4 plays a role in cell division, migration, differentiation, as well as apoptosis, and is frequently overexpressed in breast and colorectal tumors. To understand the role of genetic variations in the regulation of ERBB4 expression, we identified new polymorphisms and investigated their functional implication and risk association with breast and colorectal cancer. Experimental Design: We screened colorectal tumors from 92 patients for genetic variants at the ERBB4 ATG −1000 bp 5′-regulatory region by denaturing high-performance liquid chromatography and sequencing. Variants were subjected to DNA-protein interaction analyses (electrophoretic mobility shift assay), reporter gene assays in breast cancer cell lines MDA134 and MDA157, and immunohistochemical analyses of breast tumors. We established genotype frequencies within a breast cancer case-control collection (1,021 cases, 1,015 population-based controls) and a colorectal cancer case-control collection (459 cases, 569 blood donors) using matrix-assisted laser desorption ionization/time of flight mass spectrometry. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were assessed by multivariate logistic regression. Results: We identified five new germ line variants −815 A>T, −782 G>T, −638 insTC, −267 C>G, and −219 del10bp. Two variants showed in vitro functional effects. The −782T allele showed lower protein binding affinity and lower promoter activity compared with the −782G allele, however, the −815T allele showed higher protein binding affinity and higher promoter activity. The −782T variant was identified as a risk allele for breast and colorectal cancer (OR, 1.59; 95% CI, 1.06-2.34 and OR, 2.21; 95% CI, 1.22-3.99, respectively). Conclusion: The ERBB4 −782 G>T polymorphism, by virtue of its in vitro functional implication and incidence, is a risk factor for breast and colorectal cancer.

Down regulation and nuclear localization of human β-defensin-1 in pleomorphic adenomas of salivary glands

Although antimicrobial peptides (AMPs) appear to have diverse functional activities in innate immunity, a few reports suggest a potential role of human beta-defensin (hBD)-1 in tumor suppression. The aim of the present study was to compare the expression patterns of hBD-1, -2 and -3 in various features of human salivary gland tissues, such as healthy parenchyma, chronic sialadenitis and intraglandular pleomorphic adenomas, with their adjacent normal tissues. Twenty human salivary gland specimens (five healthy, five chronic sialadenitis, five pleomorphic adenomas and five adenoma adjacent normal tissues (AANTs)) were investigated for mRNA expression levels of hBD-1, -2 and -3 by quantitative real-time RT-PCR. Additionally, immunohistochemistry for the hBD-1, -2 and -3 peptides was performed for analysis of localization. Considerably increased, 80-fold higher hBD-1 and increased hBD-3 mRNA expression levels compared to healthy salivary gland tissues were detected in chronic sialadenitis. In pleomorphic adenomas hBD-2 expression levels were lower, but hBD-1 expression levels were significant decreased (p=0.03) compared to healthy parenchyma. Interestingly, the AANTs showed a 48-fold higher expression of hBD-1 and increased hBD-3 expression compared to the healthy salivary gland. Immunohistochemistry of the tumors showed nuclear hBD-1 localization. For the first time, it was shown that hBD-1 gene expression is significantly decreased in pleomorphic adenomas, while simultaneously the protein is localized in the nucleus. Increased expression levels in glandular inflammation have been described previously albeit not in AANTs. These data support the hypothesis that hBD-1 might be a potential tumor suppressor also in benign salivary gland tumors in addition to other genetic alterations.

N-acetyltransferase 2, exposure to aromatic and heterocyclic amines, and receptor-defined breast cancer.

The role of N-acetyltransferase 2 (NAT2) polymorphism in breast cancer is still unclear. We explored the associations between potential sources of exposure to aromatic and heterocyclic amines (AHA), acetylation status and receptor-defined breast cancer in 1020 incident cases and 1047 population controls of the German GENICA study. Acetylation status was assessed as slow or fast. Therefore, NAT2 haplotypes were estimated using genotype information from six NAT2 polymorphisms. Most probable haplotypes served as alleles for the deduction of NAT2 acetylation status. The risks of developing estrogen receptor &agr; (ER) and progesterone receptor (PR)-positive or negative tumors were estimated for tobacco smoking, consumption of red meat, grilled food, coffee, and tea, as well as expert-rated occupational exposure to AHA with logistic regression conditional on age and adjusted for potential confounders. Joint effects of these factors and NAT2 acetylation status were investigated. Frequent consumption of grilled food and coffee showed higher risks in slow acetylators for receptor-negative tumors [grilled food: ER−: odds ratio (OR) 2.57, 95% confidence interval (CI) 1.07–6.14 for regular vs. rare; coffee: ER−: OR 2.55, 95% CI 1.22–5.33 for ≥4 vs. 0 cups/day]. We observed slightly higher risks for never smokers that are fast acetylators for receptor-positive tumors compared with slow acetylators (ER−: OR 1.32, 95% CI 1.00–1.73). Our results support differing risk patterns for receptor-defined breast cancer. However, the modifying role of NAT2 for receptor-defined breast cancer is difficult to interpret in the light of complex mixtures of exposure to AHA.

CD56 expression aids in the differential diagnosis of cholangiocarcinomas and benign cholangiocellular lesions

CD56 (neuronal cell adhesion molecule, N-CAM) has been reported in neuroendocrine tumours and as a marker of reactive biliary epithelial cells. However, up to date, it is not used to distinguish malignant from non-malignant biliary lesions. In this study, we systematically examined CD56 expression on 98 tumours arising from the biliary tree as well as intrahepatic conditions with reactive neoductules. When neuroendocrine carcinomas are excluded, only 4 of 32 (12.5%) cholangiocarcinomas expressed CD56, 2 of which showed clear cell morphology. Reactive bile ductules adjacent to cirrhotic nodules as well as in focal nodular hyperplasia were CD56 positive. Twelve of 17 (70.5%) bile duct adenomas were CD56 positive, whereas von Meyenburg complexes expressed CD56 only very focally in less than 5% of lesional cells. Bile duct cysts were negative for CD56 with the exception of focally interspersed neuroendocrine cells, similar to that seen in segmental bile ducts. Thus, if van Meyenburg complexes are excluded, CD56 can be used to differentiate intrahepatic non-neoplastic from neoplastic proliferations, which is a helpful diagnostic tool in small liver biopsies.

Polymorphisms in the UBC9 and PIAS3 genes of the SUMO-conjugating system and breast cancer risk

SUMOylation consists in the covalent conjugation of small ubiquitin-related modifiers to target proteins. SUMOylation participates in processes that are tightly linked to tumorigenesis, and genetic variability in the SUMO-conjugating system may influence the development of breast cancer. We recently reported that variation in the UBC9 gene encoding the SUMO-conjugating enzyme may affect the grade of breast tumors. Following comprehensive in silico analyses for detection of putative functional polymorphisms in 14 genes of the SUMO system, we selected one coding SNP in PIAS3 and seven tag SNPs in UBC9 for association analyses. Results were based on 1,021 cases, and 1,015 matched controls from the population-based GENICA study. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by conditional logistic regression. To explore the association with polymorphisms closely linked to the genotyped variants, multiple imputation based on HapMap data was applied. The study revealed associations of four UBC9 polymorphisms with risk of grade 1 tumors. Comparison of genotype and haplotype models indicated that the best representation of risk solely relied on rs7187167 under dominant penetrance. Women carrying the rare allele showed an increased risk of grade 1 tumors compared with common homozygotes (OR 1.87, 95% CI 1.18–2.95). This effect appeared to be stronger in women with a family history of breast or ovarian cancer. Imputation of polymorphisms in a 300-kb region around the genotyped polymorphisms identified no variants with stronger associations. Our findings suggest that genetic variation in UBC9 may affect the risk of grade 1 breast tumors.

Intrahepatic Clear cell cholangiocarcinoma: Immunohistochemical aspects in a very rare type of cholangiocarcinoma

Clear cell cholangiocarcinoma is a very unusual variant of peripheral bile duct carcinoma. We present 3 cases on which we performed a broad spectrum of immunohistochemical analysis. The tumors showed a glandular and trabecular growth pattern with abundant desmoplastic stroma and clear cell change of about 80% of the tumor cells. Positive expression of CK7 indicated a cholangiocellular origin. A primary hepatocellular carcinoma and metastatic clear cell tumors of the kidney, gastrointestinal tract, and the thyroid gland were excluded by absence of CK20, CD10, HepPar1, and TTF1. No mucin could be detected within the cytoplasm of the clear cells. Electronmicroscopy revealed only a few glycogen granula, but numerous cytoplasmic lipoid vacuoles as a possible explanation for the clear cell phenotype. All 3 tumors exhibited positive expression of CD56 (NCAM) in a significant amount of the clear cells. Beside the clear cell component, one tumor also showed an adenocarcinomalike and a well-differentiated tubular component. CD56 expression was detected in all 3 tumor areas. This report of 3 cases demonstrates that clear cell cholangiocarcinomas are not only of unusual histomorphology. They also show CD56 expression which is a very uncommon finding for intrahepatic cholangiocarcinomas. As CD56 expression is also found in reactive bile ducts and bile duct adenomas, one may speculate that these rare neoplasms may originate from reactive bile ducts or cholangiomatous lesions.