Mutation Spectrum in Liquid Versus Solid Biopsies From Patients With Advanced Gastroenteropancreatic Neuroendocrine Carcinoma.

Gastroenteropancreatic neuroendocrine carcinomas (GEP-NEC) are rare and have a poor prognosis. Most GEP-NEC are diagnosed with metastatic disease, with only minor biopsies available for molecular diagnostics. We assessed the applicability of liquid biopsies for molecular profiling of GEP-NEC. We performed massive parallel sequencing of 76 cancer-related genes in circulating tumor DNA from 50 patients with advanced GEP-NEC and compared findings to previous analyses of solid tumor biopsies from the same patients. Plasma samples were collected before therapy, and the median time span between blood and tissue sampling was 25 days. We detected 178 somatic mutations in the liquid biopsies, 127 (71%) were also detected in the solid biopsies, whereas 51 (29%) were unique to the liquid biopsies. In the same 76 genes, we previously detected 199 somatic mutations (single nucleotide variants) in solid biopsies, of which 127 (64%) were also now detected in liquid biopsies. In exploratory subgroup assessments, concordance was higher in patients with liver metastases ( Liquid biopsy analyses may be an applicable alternative to solid biopsies in GEP-NEC. Liquid biopsies may add additional mutations compared with tumor biopsies alone and could be useful for biomarker assessment in clinical trials for these patients.