Comparison among Various Prognostic Pathologic Markers Revealed Significantly Poorer Prognosis in Non-basal-like than in Basal-like Triple Negative Breast Cancer

Objective: To find the incidence and prognosis of basal-like (TNB) and non-basal-like (TNN) in triple negative breast cancer. Methods: Triple negative breast cancer (TN) cases were retrospectively reviewed and biomarkers studied on tissue microarray for ER, PR, HER2, Ki67, basal cytokeratins (CK5/6, CK14, CK17), EGFR, CD117, p63, p53, vimentin, CK7, CK8/18, CK19, BCL2, p16, WT1, and cyclin D1. The patients were reclassified according to ER, PR, HER2, Ki67 index, basal CKs and EGFR results into: lumA, lumB, HER2+, TNB and TNN. Results: From 2007 to 2010, there were 193 female patients (120 TNB, 17 TNN, 42 lumB, and 14 HER2+). There were 184 (95.3%) invasive ductal carcinoma (IDC). All 17 TNN were IDC. High grade histology accounted for 71.5%. The median follow up time was 62.93 months. There were no significant differences in age, histologic grade, and tumor size between TNB and TNN while TNN had significant number of higher stage (p=0.028), axillary lymph node metastasis of more than 3 nodes (p=0.005) and lower disease free survival (DFS, p= 0.004) and overall survival (OS, p=0.001). TNN also had the poorest prognosis among the four subtypes.Tumor size and axillary nodal involvement were the independent predictors for DFS and OS. Absence of EGFR expression was an independent factor for lower DFS and OS in TN. Absence of CK8/18 expression was an independent factor for lower DFS in any combined group and OS in the combined TN and lumB group. Absence of p16 expression was an independent factor for lower DFS and OS of all cohort. Conclusion: TNN accounted for12.3% of TN and had poorer prognosis. Tumor size and axillary nodal involvement were the independent predictors for DFS and OS. Absence of EGFR, CK8/18 or p16 expression had influence on survival in TN or combined group.