TACC2 (transforming acidic coiled-coil protein 2) in breast carcinoma as a potent prognostic predictor associated with cell proliferation

Transforming acidic coiled-coil protein 2 (TACC2) belongs to TACC family proteins and involved in a variety of cellular processes through interactions with some molecules involved in centrosomes/microtubules dynamics. Mounting evidence suggests that TACCs is implicated in the progression of some human malignancies, but significance of TACC2 protein in breast carcinoma is still unknown. Therefore, in this study, we examined the clinical significance of TACC2 in breast carcinoma and biological functions by immunohistochemistry and in vitro experiments. Immunohistochemistry for TACC2 was performed in 154 cases of invasive ductal carcinoma. MCF-7 and MDA-MB-453 breast carcinoma cell lines were transfected with small interfering RNA (siRNA) for TACC2, and subsequently, cell proliferation, 5-Bromo-2-deoxyuridine (BrdU), and invasion assays were performed. TACC2 immunoreactivity was detected in 78 out of 154 (51%) breast carcinoma tissues, and it was significantly associated with Ki-67 LI. The immunohistochemical TACC2 status was significantly associated with increased incidence of recurrence and breast cancer-specific death of the patients, and multivariate analyses demonstrated TACC2 status as an independent prognostic factor for both disease-free and breast cancer-specific survival. Subsequent in vitro experiments showed that TACC2 significantly increased the proliferation activity of MCF-7 and MDA-MB-453. These results suggest that TACC2 plays an important role in the cell proliferation of breast carcinoma and therefore immunohistochemical TACC2 status is a candidate of worse prognostic factor in breast cancer cases.