Our aim was to evaluate the KRAS genotypes of Japanese colorectal cancer (CRC) patients and to assess the effect of these genotypes on clinical outcome. A total of 99 patients with stage I-IV CRC who underwent resection were prospectively studied for KRAS mutations by direct sequencing. KRAS mutations were found in 37 (37.4%) of 99 patients. Of these, 11.1% were the KRAS p.G13D mutation and the remaining 26.2% were other KRAS mutations. The cumulative 5-year survival rates for patients with wild-type KRAS, KRAS 12 and KRAS p.G13D mutations were 81.4, 61.4 and 42.0%, respectively (P=0.0397). The KRAS genotype had no effect on stage IV patient prognosis without anti-epithelial growth factor receptor (EGFR) antibody therapy. However, in stage I-III patients significant or trends in prognostic factors for disease-free survival (DFS) were pathological T stage, lymphatic vessel involvement and KRAS p.G13D. Multivariate analysis identified T4 pathological stage (P=0.0076) and the KRAS p.G13D mutation (P=0.0499) as the most significant independent prognostic factors associated with DFS. In Japanese CRC patients KRAS p.G13D had prognostic impact on DFS in stage I-III disease, while the prognosis of stage IV patients without anti-EGFR antibody therapy was unaffected by KRAS status.

PMID: 22922794 [PubMed - as supplied by publisher] Source: National Library of Medicine.