Detection of mutant K-ras in dissected paraaortic lymph nodes of patients with pancreatic adenocarcinoma.

In this study, we attempted to detect K-ras point mutations by means of two-stage polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) to diagnose micrometastases in paraaortic lymph nodes of patients with pancreatic adenocarcinoma. Main carcinoma tissues and corresponding lymph nodes in the paraaortic region were obtained from 15 patients who underwent extended radical surgery including the wide dissection of lymph nodes and who were diagnosed as lymph node negative by routine histological examination. DNA was extracted from the tissue specimens, and PCR/RFLP analysis was used to detect K-ras oncogene mutations at codon 12. Thirteen of the primary tumors were found to have K-ras mutations. In eight of the 13 cases, 42 of the 101 lymph nodes showed K-ras point mutations in the paraaortic lymph nodes. These results suggested that PCR/RFLP analysis is potentially highly sensitive for the detection of micrometastases in lymph nodes and that it may be useful in reaching an accurate assessment of the lymphatic dissemination of pancreatic adenocarcinoma at the molecular level.