Differences in prognosis and efficacy of chemotherapy by p53 expression in triple-negative breast cancer

Purpose: TP53 mutation is the most common mutation in breast cancer, and it is considered a target marker of triple-negative breast cancer (TNBC). We investigated whether expression of p53 detected by immunochemical staining predicts the chemotherapy response of TNBC. Methods: A total of 11,393 TNBC patients who had between stage I and stage III enrolled in the Korean Breast Cancer Society Registry database from January 1, 2000 to December 31, 2015. There were 6,331 ‘p53-positive (+) TNBC’ patients and 5062 ‘p53-negative (−) TNBC’ patients. Results: In univariate analysis, p53(+) TNBC had a worse prognosis than p53(−) TNBC in patients not receiving chemotherapy (P = 0.003). However, there was no difference in prognosis between p53(+) TNBC and p53(−) TNBC for patients receiving chemotherapy. In multivariate analysis adjusted for age and stage, the risk of p53(+) TNBC was 1.84 times higher than that of p53(−) TNBC in the non-chemotherapy group. However, there was no difference between p53(+) TNBC and p53(−) TNBC in patients receiving chemotherapy. In p53(+) TNBC, the risk was 0.6-fold lower when chemotherapy was administered than when chemotherapy was not administered. However, in p53(−) TNBC, there was no risk reduction effect by chemotherapy. Conclusion: The prognosis of p53(+) TNBC has worse than p53(−) TNBC, but the risk for survival was significantly reduced with chemotherapy. It suggests that p53(+) TNBC would be more sensitive to chemotherapy than p53(−) TNBC.