Results and Discussion
The demographic and clinical characteristics of the patients with BTC, including age, sex, cancer stage, recurrence, and survival, are summarized in Table 1.
The patients included three females and four males with an average age of 60 years. Among the seven patients, five patients were defined as experiencing recurrence of disease after surgery.
We analyzed whole-exome sequencing data of matched tumor and normal DNA from the patients. The mean coverage depth for all samples is demonstrated in Supplementary Table 1. In total, 274 somatic mutations in protein-coding regions were called by both callers, Strelka and Mutect. The average number of somatic mutations per case was 34, showing a range of 25 to 59 (Fig. 1). We found two patients harboring activating mutations in KRAS, such as G12V and G13D (Table 2). Missense mutations in codon 61 of the NRAS gene and codon 766 of the NTRK1 gene were also detected in two patients. A nonsense mutation in TP53 was found in a patient, and APC was inactivated by frameshift mutations in two patients. A patient harbored a frameshift mutation that was caused by a deletion of G in the ARID1A gene. Detailed information on the somatic mutations is provided in Supplementary Table 2.
This study analyzed somatic mutations using WES in a limited number of patients with BTC. To understand the genetic features of BTC, more data need to be analyzed from more patients.