Abstract P4-04-08: Genomic profiling of 304 treatment-naïve Chinese breast cancer patients: A comparison of Chinese and TCGA cohorts

Abstract Background: The complexity of BC at the clinical, morphological and molecular level has been well recognized. Molecular profiling, which reveals the intrinsic biology among subtypes, has significantly advanced the management of this disease. However, previous studies have provided very limited molecular data on Chinese breast cancer patients. Methods: We performed targeted sequencing using a panel consisting of 36 BC related genes to interrogate the genomic landscape of 304 consecutive treatment-naïve Chinese BC patients and compared our results to the TCGA data set. Results: Comparing to TCGA, our cohort had significantly fewer patients with triple negative breast cancer (8.2% vs 15.5% p=0.002). The most prominent genomic difference was our cohort had significantly higher TP53mutation frequency in HR+/HER2- and HR+/HER2+ groups. The composition of TP53 mutations also differed significantly between two cohorts in HR+/HER2- group, with TCGA cohort having missense mutation as the predominant mutation; whereas, in our cohort, nonsense and frameshift mutations were predominant. We classified the most populated and diverse group of HR+/HER2- cancer into 4 subgroups based on molecular signature. The clinical significance of this proposed classification was confirmed by differences in overall survival using data from the TCGA. Conclusions:We identified distinctive genomic patterns associated with Chinese breast cancer patients compared to TCGA data, suggesting the importance of mutation-based stratification according to ethnic status. To the best of our knowledge, this is one of the largest study of Chinese BC patients that interrogated the spectrum of mutational events and correlated these molecular signatures with clinical outcomes. This study was supported by funding from National Natural Science Foundation of China (Grant No. 81602645), Guangdong Provincial Natural Science Foundation (Grant No. 2016A030313768) and Research Funds from Guangzhou Science and Technology Bureau (Grant No. 201707010418 and 201804010430). Citation Format: Liao N, Zhang G, Wang Y, Guo L, Cao L, Zhang Z, Balch CM, Meric-Bernstam F. Genomic profiling of 304 treatment-naïve Chinese breast cancer patients: A comparison of Chinese and TCGA cohorts [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-04-08.