Clinicopathological Features and Survival Analysis of Breast Cancer Subgroups

Descriptive statistics of the clinicopathologic features of the 473 tumors were calculated. All cases of Group 2 were grouped for different cutoffs of average HER2 signals, average CEP17 signals, and HER2/CEP17 ratio, respectively. Various tumor characteristics were compared between these groups using the Pearson chi-square test aiming at evaluating the relationship between different groups. A total of 57 patients of Group 2 who were primary breast cancer without neoadjuvant therapy and underwent modified radical mastectomy were selected and matched with 374 patients of Group 5 for further comparison analysis of clinicalpathological characteristics. The Fisher exact tests were performed when necessary. All statistical tests were two-sided, and P values less than 0.05 were considered as significant. Disease free survival (DFS) was the primary end point, defined as local or regional recurrence, distant metastasis, or death from any cause. DFS and overall survival (OS) of Group 2 were estimated using the Kaplan-Meier method. All analyses were performed in SPSS (version 17.0, SPSS Company, Chicago, IL).