HIP1 expression predicts outcome in breast cancer patients treated with neoadjuvant chemotherapy

Abstract

IntroductionHuntingtin-interacting protein 1 (HIP1) binds to inositol and clathrin, which is related to neurodegeneration. Signaling of growth factors receptors through clathrin is one mechanism by which cells regulate intracellular signaling. High levels of HIP1 protein have been observed in breast, colon, kidney, lung, ovarian and prostate cancer and melanoma. MethodsTumor biopsies were obtained from 83 breast cancer patients (p) treated with four cycles of fluorouracil, epirubicin and cyclophosphamide neoadjuvant chemotherapy. Estrogen receptor, progesterone receptor, HER2, cytokeratin 5/6, vimentin and HIP1 were examined by tissue microarray. HER2 was also assessed by chromogenic in situ hybridization and the prognostic and predictive value of HIP1 expression was evaluated. ResultsHIP1 was evaluated by immunohistochemistry (IHC) in 83 p, considered negative if the result was 0, and positive if it was 1, 2 or 3. The result was 0 in 11 p (13.3%), 1 in 40 p (48.2%), 2 in 25 p (30.1%), and 3 in 7 p (8.4%). Negative HP1 was correlated with poorly differentiated tumors (p=0.021) and triple negative tumors (p=0.038). Negative HIP1 was not correlated with response but HIP1 negative was correlated with shorter time to progression (TTP) (p=0.003) and overall survival (OS) (p=0.009). ConclusionsHIP1 could be a prognostic and predictive factor in breast cancer.