Targeting the Sequences of Circulating Tumor DNA of Cholangiocarcinomas and Its Applications and Limitations in Clinical Practice.

Cholangiocarcinoma is a malignant epithelial tumor arising from bile ducts that is frequently fatal. Diagnosis is difficult due to tumor location in the biliary tract. Earlier diagnosis requires less invasive methods of identifying effective biomarkers for cholangiocarcinoma. The present study investigated the genomic profiles of cell-free DNA (cfDNA) and DNA from corresponding primary cholangiocarcinomas using a targeted sequencing panel. Somatic mutations in primary tumor DNA and circulating tumor DNA (ctDNA) were compared and clinical applications of ctDNA validated in patients with cholangiocarcinoma. A comparison of primary tumor DNA and ctDNA identified somatic mutations in patients with early cholangiocarcinomas that showed clinical feasibility for early screening. The predictive value of single-nucleotide variants (SNVs) of preoperative plasma cfDNA positive for somatic mutations of the primary tumor was 42%. The sensitivity and specificity of postoperative plasma SNVs in detecting clinical recurrence were 44% and 45%, respectively. Targetable fibroblast growth factor receptor 2 (FGFR2) and Kirsten rat sarcoma virus (KRAS) mutations were detected in 5% of ctDNA samples from patients with cholangiocarcinoma. These findings showed that genomic profiling of cfDNA was useful in clinical evaluation, although ctDNA had limited ability to detect mutations in cholangiocarcinoma patients. Serial monitoring of ctDNA is important clinically and in assessing real-time molecular aberrations in cholangiocarcinoma patients.