Evaluation of the Predictive Value of Her-2/neu Overexpression and p53 Mutations in High-Risk Primary Breast Cancer Patients Treated With High-Dose Chemotherapy and Autologous Stem-Cell Transplantation

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Abstract
PURPOSE: To ascertain the predictive value of Her-2/neu overexpression and p53 mutations, assessed by immunohistochemistry, in high-risk primary breast cancer (HRPBC) treated with high-dose chemotherapy (HDCT). PATIENTS AND METHODS: We obtained paraffin-embedded tumor blocks from 146 HRPBC patients previously enrolled at our program onto clinical trials of HDCT for four to nine involved axillary lymph nodes, ≥ 10 involved axillary nodes, or inflammatory carcinoma. All patients received the same HDCT regimen, with cyclophosphamide, cisplatin, and carmustine (STAMP-I), followed by autologous stem-cell transplantation. Median follow-up was 42 months (range, 5 to 90 months). The same pathologist, blinded to clinical outcome, reviewed all immunostained slides. RESULTS: Positive results for Her-2/neu and p53 were found in 44.5% and 34% of the patients, respectively. Positivity for Her-2/neu was significantly associated with increased risk of relapse and death. No correlation was found between p53 mutations and relapse-free survival (RFS) or overall survival (OS). Multivariate analyses included Her-2/neu overexpression and the following variables previously identified as independent predictors of outcome in this population: tumor size, nodal ratio (number of involved nodes/number of dissected nodes), and hormone receptor status. All four variables had independent value. CONCLUSION: Her-2/neu overexpression is an independent negative predictor of RFS and OS in HRPBC treated with HDCT. Its inclusion in our previously described predictive model increases the predictive capacity of this model for the low-risk subgroup. In contrast, p53 mutations lack predictive value in this setting.