DETECTION OF K-RAS POINT MUTATIONS IN MESENTERIC VENOUS-BLOOD FROM COLORECTAL-CANCER PATIENTS BY ENRICHED POLYMERASE CHAIN-REACTION AND SINGLE-STRAND CONFORMATION POLYMORPHISM ANALYSIS

In order to confirm the presence of cancer cells in mesenteric venous blood and to examine their relationship with the occurrence of liver m etastases, we attempted to detect K-ras codon 12 point mutations in pe rioperative mesenteric blood using enriched polymerase chain reaction and single-strand conformation polymorphism (PCR-SSCP) analysis in 25 patients with primary colorectal tumors carrying K-ras point mutations . Among these patients, three with synchronous liver metastases were i ncluded. The same K-ras point mutation (substitution of CAT for CCT) w as detected in both the blood and the primary tumor in a Dukes' C pati ent. We confirmed this result by colony hybridization and estimated th e tumor-to-normal cell ratio to be 1:400. This patient has no liver me tastases two years after surgery and her carcinoembryonic antigen (CEA ) level remains normal. We demonstrated that considerable numbers of c ancer cells can be found in mesenteric venous blood during colorectal cancer surgery. However, their potential role in the formation of live r metastases remains unclear.