Abstract P4-07-08: The prognostic significance of ataxia-telangiectasia-mutated (ATM) and p53 expression in breast cancer

The purpose of this study was to investigate the correlation of ataxia-telangiectasia-mutated (ATM) protein and p53 expression with clinicopathological features and prognosis in patients with sporadic breast cancers. The expression of ATM and p53 was determined by immunohistochemistry in 420 surgically resected breast cancers. Loss of ATM was observed in 126 out of 407 evaluable cases (31.0%), and was significantly associated with aggressive features with large tumor size, lymph node metastasis, higher tumor grade, and negativity of ER and/or PR. ATM loss was associated with a significantly shorter disease-free survival (DFS) (p = 0.019). Abnormal p53 expression was found in 39.3% of tumors (157 out of 400), conferring a worse DFS as well (p = 0.002). When investigated together, combined ATM and p53 expression status were associated with a worse DFS (p = 0.002). On multivariate analysis, ATM loss and abnormal p53 expression status was an independent predictor of poorer DFS (intact ATM and normal p53 vs. ATM loss and abnormal p53, HR 3.350; 95% CI 1.496 - 7.502; p = 0.003). Furthermore, in patients treated with adjuvant anthracyclines, either p53 alone or p53 combined with ATM significantly influenced DFS (p = 0.004, p = 0.015, respectively). The present study demonstrates that expression of ATM and p53 is an independent prognostic marker in breast cancers, and might be a practical tool for predicting benefits from anthracycline-based adjuvant therapy. Citation Format: Suh KJ, Ryu HS, Lee K-H, Im S-A, Kim T-Y, Kim H, Yang Y, Moon H-G, Han S-W, Oh D-Y, Han W, Kim T-Y, Park IA, Noh D-Y, Bang Y-J. The prognostic significance of ataxia-telangiectasia-mutated (ATM) and p53 expression in breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-07-08.