K-ras mutation at codon 12 in stage I pancreatic adenocarcinoma: analysis by laser capture microdissection and direct sequencing.
Pancreatic ductal adenocarcinoma has been reported to carry a rate mutation high in codon 12 of the K-ras oncogene. To avoid the pitfalls of conventional methods of tissue dissection that might affect the sensitivity and specificity of detecting K-ras mutation, laser capture microdissection (LCM) technique was used. Pancreatic adenocarcinoma tissues were obtained from 15 patients who underwent Whipple's procedure. Selected tissues procured by LCM were analyzed by direct sequencing after polymerase chain reaction amplification of K-ras sequences at codon 12. K-ras mutation was noted in nine patients. All mutations showed G to A substitution at codon 12. The mutational pattern (GGT to GAT) is similar in both western and eastern reports. LCM is a feasible method to effectively obtain pure tumor cells from a surgical specimen. It remains to be determined whether this low mutation rate is a result of relatively early stage of disease or different carcinogenesis in different geographic regions.