Detection of pancreatic carcinoma: diagnostic value of K-ras mutations in circulating DNA from serum.

Somatic activating mutations at codon 12 of the K-ras gene are present in the majority of exocrine pancreatic cancers and occur early in tumorgenesis. The aim of this study was to test the feasibility of using a mutated K-ras gene from the serum as a potential tumor marker for detection of exocrine pancreatic carcinoma. Codon 12 K-ras mutations were examined in DNA extracted from the sera of 20 patients with pancreatic carcinomas, six patients with chronic pancreatitis, and five healthy individuals. K-ras gene mutations at codon 12 were detected in the sera of 14 of 20 patients with pancreatic carcinoma and in none of the six patients with chronic pancreatitis, or in the five healthy controls. Elevation of either CA19-9 or K-ras mutation was detected in 19/20 patients. These results suggest that K-ras abnormalities in serum could be used as a potential tumor marker in patients with a pancreatic lesion. The absence of K-ras mutations in serum and presence of CA19-9 in the normal range make the diagnosis of pancreatic cancer unlikely.