Clinicopathologic and Prognostic Significance of the Zinc Finger of the Cerebellum Family in Invasive Breast Cancer

Purpose Five members of the zinc finger of the cerebellum (ZIC) family-ZIC1, ZIC2, ZIC3, ZIC4, and ZIC5-have been shown to be involved in various carcinomas. Here, we aimed to explore the clinicopathologic and prognostic roles of ZIC family members in invasive breast cancer patients using immunohistochemical analysis, western blotting analysis, and real-time quantitative polymerase chain reaction (RT-qPCR). Methods A total of 241 female invasive breast cancer patients who underwent radical mastectomy between 2009 and 2011 were enrolled. ZIC proteins in 241 pairs of breast tumors and corresponding normal tissues were investigated using immunohistochemistry and the clinicopathologic roles of proteins were analyzed using Pearson's chi-square test. Kaplan-Meier curves and Cox regression analysis were also used to analyze the prognostic value of the ZIC proteins. In addition, 12 pairs of fresh-frozen breast tumors and matched normal tissues were used in the western blotting analysis and RT-qPCR. Results Only ZIC1 expression in normal tissues was obviously higher than that in tumors (p<0.001). On multivariate analysis, ZIC1 expression (in overall survival analysis: hazard ratio [HR], 0.405, 95% confidence interval [CI], 0.233-0.702, p=0.001; in disease-free survival analysis: HR, 0.395, 95% CI, 0.234-0.669, p=0.001) was identified as a prognostic indicator of invasive breast cancer. Conclusion ZIC1, but not the other proteins, was obviously decreased in breast tumors and associated with clinicopathologic factors. Thus, ZIC1 might be a novel indicator to predict the overall and disease-free survival of invasive breast cancer patients.