Genetic mutation profile of Chinese HER2-positive breast cancers and genetic predictors of responses to Neoadjuvant anti-HER2 therapy
Kai Li, Ning Liao, Bo Chen, Guochun Zhang, Yulei Wang, Liping Guo, Guangnan Wei, Minghan Jia, Lingzhu Wen, Chongyang Ren, Li Cao, Hsiaopei Mok, Cheukfai Li, Jiali Lin, Xiaoqing Chen, Zhou Zhang, Ting Hou, Min Li, Jing Liu, Charles M. Balch, Ning Liao
Abstract
PURPOSE: Despite the therapeutic success of existing HER2-targeted therapies, tumors respond quite differently to them. This study aimed at figuring out genetic mutation profile of Chinese HER2-positive patients and investigating predictive factors of neoadjuvant anti-HER2 responses. METHODS: We employed two cohorts. The first cohort was comprised of 181 HER2-positive patients treated at Guangdong Provincial People's Hospital from 2012 to 2018. The second cohort included 40 patients from the first cohort who underwent HER2-targeted neoadjuvant chemotherapy. Genetic mutations were characterized using next-generation sequencing. We employed the most commonly used definition of pathological complete response (pCR)-eradication of tumor from both breast and lymph nodes (ypT0/is ypN0). RESULTS: In Chinese HER2-positive breast cancer patients, TP53 (74.6%), CDK12 (64.6%) and PIK3CA (46.4%) have the highest mutation frequencies. In cohort 2, significant differences were found between pCR and non-pCR groups in terms of the initial Ki67 status, TP53 missense mutations, TP53 LOF mutations, PIK3CA mutations and ROS1 mutations (p = 0.028, 0.019, 0.005, 0.013, 0.049, respectively). Furthermore, TP53 LOF mutations and initial Ki67 status (OR 7.086, 95% CI 1.366-36.749, p = 0.020 and OR 6.007, 95% CI 1.120-32.210, p = 0.036, respectively) were found to be predictive of pCR status. CONCLUSION: TP53 LOF mutations and initial Ki67 status in HER2-positive breast cancer are predictive of pCR status after HER2-targeted NACT.