Analysis of KRAS and NRAS mutations in Greek patients with metastatic Colorectal Cancer (mCRC) on the registry of the Gastro-intestinal Cancer Study Group (GIC-SG)

Introduction Several studies show that mutational profiles could influence treatment decisions in patients with metastatic CRC (mCRC). KRAS mutational status was the first step in biomarkers development in the era of molecular targeted therapies. Recently, NRAS mutational status was identified as an independent prognostic factor for the response to treatment with anti-EGFR moAbs. The aim of this observational study was to assess the feasibility of the KRAS/NRAS mutational analysis in patients with metastatic colorectal cancer in Greece and to identify any correlations with known clinical characteristics and histopathologic features. Methods From January 2014 until September 2014 all patients registered to the GIC-SG database with newly diagnosed metastatic disease from colon or rectal cancer were included and tumor samples were analyzed for kras/nras mutations in 9 different certified laboratories in Greece. Results Samples from 510 patients were analyzed. Mutations’ distribution was as follows: 173 (33,9%) KRAS exon 2, 10 (2%) KRAS exon 3, 25 (4,9%) KRAS exon 4, 22 (4,3%) NRAS exon 2, 11 (2,2%) NRAS exon 3 and 3 (0,6%) NRAS exon 4. The only factor significantly associated with RAS mutational status was primary tumor location, with right sided tumors exhibiting higher rates of mutations. Discussion The incidence and distribution of KRAS or NRAS exon 2-4 mutations are in accordance with those reported in the literature. The most significant clinical or pathological parameter revealed from the analysis is the location of the primary tumor.