Independent Negative Prognostic Role of TCF1 Expression within Wnt/β-Catenin Signaling Pathway in Primary Breast Cancer Patients

Wnt pathway is involved in breast cancer (BC) progression. Our aim was to evaluate the expression of some components of the Wnt pathway (β-catenin, FZD4, LRP5, LRP6 and TCF1) in order to detect potential associations with NHERF1 protein. In addition, we assessed their impact on patients’clinical outcome. We evaluated 220 primary BC samples by immunohistochemistry (IHC) and protein localization by immunofluorescence. We found a significant correlation between NHERF1 and FZD4, LRP5, LRP6 and TCF1. Univariate analysis showed that β-catenin (p<0.0001), FZD4 (p=0.0001), LRP5, LRP6 and TCF1 over-expression (p<0.0001 respectively) was related to poor disease free survival (DFS). A Kaplan-Meier analysis confirmed univariate data and showed a poor DFS for cNHERF1+/FZD4+ (p=0.0007), cNHERF1+/LRP5+ (p=0.0002), cNHERF1+/LRP6+ (p<0.0001) and cNHERF1+/TCF1+ phenotypes (p=0.0034). In multivariate analysis, TCF1 and β-catenin expression were independent prognostic variable of worse DFS (p=0.009 and p=0.027, respectively). In conclusion, we found that β-catenin, FZD4, LRP5, LRP6 and TCF1 overexpression was associated to poor prognosis. Furthermore, we first identified TCF1 as independent prognostic factor of poor outcome, indicating it as a new potential biomarker for BC patients management. In addition, Wnt pathway proteins expression, both alone and in association with NHERF1, suggests original associations of biological significance for new studies.