ABSTRACT
KRAS mutations in patients with metastatic colorectal cancer (CRC) are a negative marker of the effectiveness of anti-EGFR therapy and have prognostic significance. KRAS genotyping was performed in the material from patients with metastatic CRC. KRAS mutations were determined in tumor DNA from archival biopsies of 573 patients using PCR and sequencing. Mutations in the exon 2 of the KRAS gene were detected in 36.3% of cases of CRC, while often in women (41.1%) than in men (31.2%). There were identified eight types of KRAS mutations, the most frequent--replacement of G12D (33.7%), G12V (32.7%) and G13D (12.5%). There were revealed differences in the frequency and spectrum of KRAS mutations in CRC of various locations; in tumors of the rectum dominated mutation G12V (39%). The Russian CRC patients find out a higher frequency of mutations G12V and a lower frequency of mutations G13D, than patients from Europe and it should be taken into account when assessing the response of CRC patients with different mutant KRAS status on chemotherapy and targeted therapy.
