Plasma PIK3CA ctDNA specific mutation detected by next generation sequencing is associated with clinical outcome in advanced breast cancer

American Journal of Cancer Research

Guohong Song¹  Yaping Xu²  Hope S Rugo³  Huiping Li⁴  Fangyuan Zhao⁵ 

[1] Department of Medicine, University of California at San Francisco, Helen Diller Family Comprehensive Cancer Center, San Francisco, USA;Geneplus-Beijing, Beijing 102206, China;Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Branch of Medical Statistics, Peking University Cancer Hospital and Institute, 52 Fucheng Rd, Beijing 100142, China;Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Breast Oncology, Peking University Cancer Hospital and Institute, 52 Fucheng Rd, Beijing 100142, China;University of Chicago, Division of The Social Sciences, 1130E, 59th Street, Chicago 60637, IL, USA

关键词: Plasma ctDNA;    next generation sequencing;    PIK3CA mutation;    clinical outcome;    advanced breast cancer;   

DOI  :  

学科分类：肿瘤学

来源: e-Century Publishing Corporation

【 摘 要 】

Through next generation sequencing, this study evaluated the circulating tumor DNA (ctDNA) of advanced breast cancer patients to prospectively explore the relationship between specific DNA mutations and prognosis as well as therapeutic decision making. The target region covered 1021 gene totally. Clinical characteristics, treatment and outcome data were collected. We analyzed progression-free survival (PFS) from first-line therapy and overall survival (OS), and found that their endpoints were correlated with observed gene mutations. We enrolled 54 patients, with a median follow-up time of 8 years. Mutations were found in TP53, PIK3CA, and ERBB family, at 40.7%, 35.2%, and 25.9%, respectively. PIK3CA more frequently occurred in the site of 3140 A>G (p.H1047R) for 20.4% and HER2+ diseases, and it was associated with shorter median PFS and worse OS among HER2+ patients [mutant vs. wild type: 4 (range 2-9) vs. 8 (range 2-22) months, P=0.006], and [mutant vs. wild type: 29 (range 12-74) vs. 64 (range 20-96) months, P=0.043], respectively. The patients with mutations in TP53 had shorter OS (median 64 vs. 121 months, P=0.006). Multivariate analysis for HER2+ disease demonstrated that the PIK3CA p.H1047R mutation was the only factor associated with shorter PFS (P=0.025); while the receiver operating characteristic (ROC) analysis produces an area under the curve (AUC) of 0.789. The ctDNA analysis, found PIK3CA p.H1047R mutation was more frequent in HER2+ disease and associated with worse OS. It was also the only mutation associated with shorter PFS through a multivariate analysis of HER2+ patients who were treated with trastuzumab, suggesting trastuzumab had lower activity in these patients. The presence of a TP53 mutation was associated with worse OS.

【 授权许可】

CC BY-NC