Unique K-ras mutational pattern in pancreatic adenocarcinoma from Taiwanese patients.

To assess the prevalence and spectrum of K-ras mutations in Taiwanese patients with pancreatic adenocarcinoma, we analyzed 20 patients of ductal adenocarcinoma of the head of the pancreas undergoing pancreaticoduodenectomy. The study included K-ras mutations that were detected using DNA direct sequencing analysis of the polymerase chain reaction products and confirmed by reverse sequencing primers. The results showed that K-ras codon 12 mutation was detected in 90% of the cancer tissues (18/20). Moreover, the results from direct sequencing indicated that missense mutations were found to be a GGT to GTT in 94.5% of the cases (17/18) and a GGT to TTT in 5.5% of the cases (1/18). All cases with K-ras codon 12 mutations were found to be G to T transversion. However, no alterations were found at codons 13 and 61. From these findings, the high prevalence of K-ras codon 12 mutation in pancreatic adenocarcinoma and the predominant G to T transversion with the preferential substitution of glycine with valine might indicate an unusual sensitivity and specificity of this codon in genetic alterations for pancreatic carcinogenesis. The strikingly high mutational rate and the unique mutational spectrum of K-ras codon 12 in Taiwanese pancreatic adenocarcinoma can provide us with more information about the alternative diagnostic and therapeutic strategies in Taiwan.