Tumour-derived mutated K-ras codon 12 expression in regional lymph nodes of stage II colorectal cancer patients is not associated with increased riskof cancer-related death

This study examined the frequency of lymph node micrometastases detected by expression of mutant K-ras oncogene present in the respective primary tumo ur. The study population consisted of consecutive patients with stage II co lorectal cancer (CRC) undergoing curative resection and with disease-free s urvival of 60 months or longer or CRC-related death. Of 27 patients found t o have K-ras mutations at codon 12, 17 had genomic DNA suitable for PCR rec overed from corresponding regional lymph node tissue. The same K-ras mutati on was identified in the lymph nodes of 13 patients (76%), four of whom (30 %) died of CRC recurrence within 5 years. A single patient in the negative group (25%) also died. Lymph node micrometastases detected by this techniqu e thus show no relationship to mortality in stage II CRC. Further study of this technique is necessary before it can be used in the selection of patie nts for adjuvant chemotherapy.