Nuclear NHERF1 expression as a prognostic marker in breast cancer.

Our purpose was to investigate whether Na(+)/H(+) exchanger regulatory factor 1 (NHERF1) expression could be linked to prognosis in invasive breast carcinomas. NHERF1, an ezrin-radixin-moesin (ERM) binding phosphoprotein 50, is involved in the linkage of integral membrane proteins to the cytoskeleton. It is therefore believed to have an important role in cell signaling associated with changes in cell cytoarchitecture. NHERF1 expression is observed in various types of cancer and is related to tumor aggressiveness. To date the most extensive analyses of the influence of NHERF1 in cancer development have been performed on breast cancer. However, the underlying mechanism and its prognostic significance are still undefined. NHERF1 expression was studied by immunohistochemistry (IHC) in a cohort of 222 breast carcinoma patients. Association of cytoplasmic and nuclear NHERF1 expression with survival was analyzed. Disease-free survival (DFS) and overall survival (OS) were determined based on the Kaplan-Meier method. Cytoplasmic NHERF1 expression was associated with negative progesterone receptor (PgR) (P=0.017) and positive HER2 expression (P=0.023). NHERF1 also showed a nuclear localization and this correlated with small tumor size (P=0.026) and positive estrogen receptor (ER) expression (P=0.010). Multivariate analysis identified large tumor size (P=0.011) and nuclear NHERF1 expression (P=0.049) to be independent prognostic variables for DFS. Moreover, the nuclear NHERF1(-)/ER(-) immunophenotype (27%) was statistically associated with large tumor size (P=0.0276), high histological grade (P=0.0411), PgR-negative tumors (P<0.0001) and high proliferative activity (P=0.0027). These patients had worse DFS compared with patients with nuclear NHERF1(+)/ER(+) tumors (75.4% versus 92.6%; P=0.010). These results show that the loss of nuclear NHERF1 expression is associated with reduced survival, and the link between nuclear NHERF1 and ER expression may serve as a prognostic marker for the routine clinical management of breast cancer patients.

Old and new concepts in histopathological characterization of familial breast cancer.

BRCA1- and BRCA2-deficient cells display genomic instability due to impaired DNA repair and may subsequently be predisposed to malignant transformation. Cancers arising in BRCA1 gene mutation carriers differ substantially from sporadic breast cancers of age-matched controls in their histopathological appearance. BRCA1-related breast cancers have been morphologically associated with poorly differentiated and medullary types, exhibiting triple negativity and 'basal phenotype'. There are different types of mutations listed in Breast Cancer Information Core professional databases and most of them are small insertions or deletions. Moreover, the search for more pathological alterations has led to identification of missense mutations, intronic variant sequences and unclassified variants, reporting an unclear role in breast cancer susceptibility. We review the latest evidence regarding analysis of various mutations in BRCA1/2 genes and low-risk breast cancer susceptibility genes. Preliminary data from our laboratories indicate that biomarkers for invasiveness may lead to better characterization of familial breast cancers. Multivariate regression analysis has allowed us to select the best combination of markers to predict familial or hereditary breast cancers. We found that a marker signature comprising human epidermal growth factor receptor 2 (HER2) negativity, Na(+)/H(+) exchanger regulatory factor 1 (NHERF1) negativity and BRCA1 positivity (designated 'triple-biomarker' signature) is frequently associated with familial breast cancer and promises to be a reliable test in its molecular characterization.