The transcription factor nuclear factor kappa B (NF-jB) is constitutively active in both cancer cells and stromal cells of breast cancer; however, the precise role of activated NF-jB in cancer progression is not known. Using parental MCF10A cells and a variant that expresses the myoepithelial marker p63 stably overexpressing the constitutively active p65 subunit of NFjB (MCF10A/p65), we show that NF-jB suppresses the expression of epithelial specific genes E-cadherin and desmoplakin and induces the expression of the mesenchymal specific gene vimentin. P65 also suppressed the expression of p63 and the putative breast epithelial progenitor marker cytokeratin 5/6. MCF10A/p65 cells were phenotypically similar to cells undergoing epithelial to mesenchymal transition (EMT). MCF10A/p65 cells failed to form characteristic acini in three-dimensional Matrigel. Analysis of parental and MCF10A/p65 cells for genes previously shown to be involved in EMT revealed elevated expression of ZEB-1 and ZEB-2 in MCF10A/ p65 cells compared to parental cells. In transient transfection assays, p65 increased ZEB-1 promoter activity. Furthermore, MCF10A cells overexpressing ZEB-1 showed reduced E-cadherin and p63 expression and displayed an EMT phenotype. The siRNA against ZEB-1 or ZEB-2 reduced the number of viable MCF10A/ p65 but not parental cells, suggesting the dependence of MCF10A/p65 cells to ZEB-1 and ZEB-2 for cell cycle progression or survival. MCF10A cells chronically exposed to tumor necrosis factor alpha (TNFa), a potent NF-jB inducer, also exhibited the EMT-like phenotype and ZEB-1/ZEB-2 induction, both of which were reversed following TNFa withdrawal.

Purpose: FOXA1, a forkhead family transcription factor, is essential for optimum expression of f50% of estrogen receptor a (ERa):estrogen responsive genes. FOXA1 is expressed in breast cancer cells. It segregates with genes that characterize the luminal subtypes in DNA microarray analyses. The utility of FOXA1 as a possible independent prognostic factor has not been determined in breast cancers. Materials and Methods: A tissue microarray comprising tumors from 438 patients with 15.4 years median follow-up was analyzed for FOXA1 expression by immunohistochemistry. Interpretable FOXA1 expression obtained in 404 patients was analyzed along with other prognostic factors like tumor grade, size, nodal status, ER, progesterone receptor (PR), and HER2/neu.Results: FOXA1expression (score >3) was seen in 300 of 404 breast cancers and it correlated with ER (P = 0.000001), PR (P = 0.00001), and luminal A subtype (P = 0.000001). Loss of expression was noted with worsening tumor grade (P = 0.001). Univariate analysis showed nodal status (P = 0.0000012), tumor size (P = 0.00001), FOXA1 (P = 0.0004), and ER (P = 0.012) to be predictors of breast cancer^specific survival. Multivariate analysis showed only nodal status (P = 0.001) and tumor size (P = 0.039) to be significant prognostic factors, whereas FOXA1 (P = 0.060) and ER (P = 0.131) were not significant. In luminal subtype A patient subgroup, FOXA1 expression was associated with better cancer-specific survival (P = 0.024) and in ER-positive subgroup, it was better predictor of cancer-specific survival (P = 0.009) than PR (P = 0.213). Conclusion: FOXA1 expression correlates with luminal subtype A breast cancer and it is significant predictor of cancer-specific survival in patients with ER-positive tumors. Prognostic ability of FOXA1 in these low-risk breast cancers may prove to be useful in clinical treatment decisions.Estrogen receptor (ER) expression is a good predictive and prognostic factor in breast cancer. However, not all ER-positive breast cancers behave alike. Knowing why and how some ER-positive breast cancers behave differently than others is important from both research and clinical viewpoint. A clinician will certainly be more pleased to know which patients with ER-positive breast cancers need to be treated aggressively and a research scientist would be interested in knowing the pathways involved in these different behaviors and if any of those can serve as therapeutic targets.Estrogen plays an important role in the growth, proliferation, and differentiation of mammary epithelium. ERa and ERh mediate the biological action of estrogen by functioning as estrogen-activated transcription factors (1, 2). ERa is expressed in 10% to 15% of luminal epithelial cells of normal breast and these cells are generally considered slowly proliferating and well-differentiated cell types (3). However, >50% of breast cancers express ERa at the time of initial diagnosis (1). These findings suggest a distinct role for ERa in the growth of normal, immortalized, and transforme...

Based on this study in patients treated with surgery followed by adjuvant anthracycline-based chemotherapy, FOXA1 expression is associated with good prognosis. It correlates with luminal subtype breast cancer, and could possibly serve as a clinical marker for luminal subtype A. Prognostic ability of FOXA1 in these low-risk breast cancers may prove to be useful in treatment decision making.

Breast cancer metastasis predominantly occurs via lymphatic vessels. However, the study of lymphatic vessels and lymphangiogenesis has been hampered by lack of specific markers. Recently, antibodies directed against M2A (D2-40), Podoplanin, and Prox-1 that specifically mark lymphatic vessels in paraffin-embedded sections have become available. These were used to study lymphangiogenesis in archival paraffin sections of normal breast (n = 23), fibrocystic disease (n = 7), ductal carcinoma in situ (n = 32), invasive ductal carcinoma (n = 50), and invasive lobular carcinoma (n = 5). In addition, endothelial proliferation in lymphatic vessels was analyzed by dual-color immunohistochemistry with D2-40 and proliferating cell nuclear antigen (PCNA). Expression of D2-40, Prox-1, and Podoplanin was seen in lymphatic vessels but not in blood vessels. Lymphatic vessels were seen in the peritumoral area and as "entrapped" intratumoral vessels adjacent to preexisting normal lobules and ducts. Unlike angiogenesis, there was no increase of lymphatic vessel density in association with neoplastic transformation. On the contrary, a marked reduction in intratumoral lymphatic vessel density was seen in comparison to normal breast tissue, fibrocystic disease, and ductal carcinoma in situ (P = 0.0001). There was an increase in peritumoral lymphatic vessel density as compared with normal breast (P = 0.0001). However, the endothelial cells in the "entrapped" or the peritumoral lymphatic vessels did not show any expression of PCNA indicating minimal or no proliferative activity. This was in contrast to the strong expression seen in adjacent tumor cells and blood vessel endothelial cells. Thus, lymphangiogenesis was not evident when studied by lymphatic vessel density or by lymph vessel endothelial proliferation.

The anti-tumour actions of cyclooxygenases (COX) are thought to be mediated by inhibition of prostaglandin E(2) (PGE(2)) synthesis. However, COX-2 inhibition also alters cellular production of other prostaglandins such as prostacyclin (PGI(2)). The latter action is believed to be important for the development of adverse cardio-vascular events. Microsomal PGES (mPGES-1) is an enzyme downstream to COX-2 and affects PGE(2) production only. It is possible that targeting mPGES-1 could decrease PGE(2) production without affecting PGI(2) production. In order to assess the potential of mPGES-1 as a target for therapy, we analysed its expression in breast cell lines and normal and malignant breast tissues. The expression of mPGES-1 and COX-2 was correlated in tumour cells and vascular endothelium, and with prognostic parameters in breast cancer. Although not detectable in normal epithelial cells, expression was noted in areas of fibrocystic change and in situ carcinoma. mPGES-1 expression was noted in 79% of breast cancer tissues. Its expression did not correlate with COX-2 overexpression or with prognostic markers of breast cancer. Endothelial cells did not show mPGES-1 expression. Upregulation of mPGES-1 is therefore frequent in pre-malignant and malignant breast disease. In this study, coordinate over-expression of COX-2 and mPGES-1 was not observed, particularly in the endothelial cells of blood vessels. Targeting mPGES-1 might prove to be an alternative therapeutic strategy to inhibit PGE2 production.