The Association between Mutations Detected in Tissue and Plasma from Patients with Colorectal Adenoma and Adenocarcinoma

Abstract

Most colorectal cancers evolve through an adenoma-carcinoma sequence with mutations in the KRAS/BRAF pathway as an early event. Mutation analyses are usually performed on tissue samples, but during the last couple of years the same analysis in blood has been facilitated. Our aim was to investigate the correlation between BRAF/KRAS mutations in tissue and plasma from colorectal adenomas and adenocarcinomas. Out of 22 patients with adenomas 10 had a mutation in the tissue, but no mutations were detected in the plasma. In 10 of 26 adenocarcinomas a mutation was found in the tumor and in four of these, the mutation was also detected in the plasma. Our results confirm previous findings that mutated DNA in plasma can be detected in approximately 50% of non-metastasized adenocarcinomas. The difference between adenomas and adenocarcinomas suggests that appearance of mutated DNA in plasma associates with invasion.