KRAS,NRASandBRAFmutations in Greek and Romanian patients with colorectal cancer: a cohort study

Abstract

ObjectivesTreatment decision-making in colorectal cancer is often guided by tumour tissue molecular analysis. The aim of this study was the development and validation of a high-resolution melting (HRM) method for the detection of KRAS, NRAS and BRAF mutations in Greek and Romanian patients with colorectal cancer and determination of the frequency of these mutations in the respective populations.SettingDiagnostic molecular laboratory located in Athens, Greece.Participants2425 patients with colorectal cancer participated in the study.Primary and secondary outcome measures2071 patients with colorectal cancer (1699 of Greek and 372 of Romanian origin) were analysed for KRAS exon 2 mutations. In addition, 354 tumours from consecutive patients (196 Greek and 161 Romanian) were subjected to full KRAS (exons 2, 3 and 4), NRAS (exons 2, 3 and 4) and BRAF (exon 15) analysis. KRAS, NRAS and BRAF mutation detection was performed by a newly designed HRM analysis protocol, followed by Sanger sequencing.ResultsKRAS exon 2 mutations (codons 12/13) were detected in 702 of the 1699 Greek patients with colorectal carcinoma analysed (41.3%) and in 39.2% (146/372) of the Romanian patients. Among the 354 patients who were subjected to full KRAS, NRAS and BRAF analysis, 40.96% had KRAS exon 2 mutations (codons 12/13). Among the KRAS exon 2 wild-type patients 15.31% harboured additional RAS mutations and 12.44% BRAF mutations. The newly designed HRM method used showed a higher sensitivity compared with the sequencing method.ConclusionsThe HRM method developed was shown to be a reliable method for KRAS, NRAS and BRAF mutation detection. Furthermore, no difference in the mutation frequency of KRAS, NRAS and BRAF was observed between Greek and Romanian patients with colorectal cancer.

Real-Life Distribution of KRAS and NRAS Mutations in Metastatic Colorectal Carcinoma from French Routine Genotyping

“…This is a unique opportunity to observe the frequency of somatic mutations of KRAS and NRAS in a nationwide population, regardless of inclusion bias such as socioeconomic factors as the tests were free of charge for the patient. The distribution of the KRAS and NRAS mutations reported in the present study was similar to data in the literature (6)(7)(8)(9)(10). No NRAS exon 3 at c.59 or exon 4 at c.117 mutations was retrieved, and only 1 mutation of NRAS c.146 (exon 4) was detected, representing only 0.05% of the whole incident population.…”

Molecular predictive markers in tumors of the gastrointestinal tract

“…FFPE tissue is a widely available material, easy to use and maintain. In addition, the cancer tissue can be selected and mutation analysis can be performed without contamination by normal tissues[42]. This increases the sensitivity of mutation detection assays which is very important because, due to tumor heterogeneity, somatic mutations can sometimes be present at a very low percentage.…”

“…Mutations in KRAS account for about 85% of all RAS mutations in human tumors, NRAS for about 15%, and HRAS for less than 1%[41,42]. Which particular RAS gene is mutated seems to be tumor specific.…”

“…Which particular RAS gene is mutated seems to be tumor specific. Colonic, pancreatic and lung cancers have high frequencies of KRAS mutations[41,42]. …”

Prevalencia y características de mutaciones somáticas del gen KRAS en pacientes chilenos con cáncer colorectal

“…La frecuencia de mutaciones en NRAS en pacientes con CCR es alrededor de 6%, e incluso se ha observado cercana a 10% en algunos países como Grecia y Rumania [30][31][32] , por lo que se ha agregado al estudio junto con KRAS antes de determinar la terapia.…”