Abstract P2-03-05: TP53 mutations in circulating tumor DNA associate with klebsiella pneumoniae inbreast cancer

Background Breast cancer is a heterogeneous disease with different molecular pathological types and different clinical manifestations. Liquid-based analysis of tumor heterogeneity in circulating tumor DNA (ctDNA) can be used for cancer detection, monitoring disease progression, etc. The gut microbiome has emerged as an important mediating factor of breast cancer. Dysbiosis may contribute to the development of breast cancer. In this study, we aimed to identify risk-associated microbiome and whether some of specific microbiomes correlate with tumor-specific mutation burdens and disease progression in Taiwan breast cancer patients. Methods A total of 141 normal female subjects and 52 breast cancer patients were enrolled randomly. The study was approved from the Internal Review Board of Kaohsiung Medical University Hospital and informed consents were obtained from each subject. The Oncomine™ breast cfDNA assays with 10-gene panel of 152-associated mutational hotspot loci was performed to detect circulating breast tumor-derived DNA (ctDNA). The microbiota composition in fecal samples was analyzed using 16S ribosome RNA gene (V3-V4 region) amplicon sequencing on Illumina Miseq platform. 16S rRNA sequencing data were analyzed using CLC genomics workbench (Qiagen, Germany) and MeTaxon software (DNArails Co., Ltd, Taipei, Taiwan, ROC). Results Multiple logistic regression was used to compare the differences of druggable gene mutations and 59.2% of patients harbored at least one somatic mutation. Compared to TP53, the odds of mutations of PIK3CA, ERBB2, AKT, KRAS, and SF3B1 were 94.4%, 98.5%, 99.3%, 99.3%, and 99.7% were significantly lower than those of TP53 (all p