The early diagnosis of pancreatic carcinoma is difficult. The serum tumor markers such as CA19-9 have a relatively high sensitivity but with low specificity. The oncogene K-ras is frequently mutated in pancreatic carcinoma and with high specificity. The aim of this study was to assess the feasibility of detection of K-ras mutation combined with serum content of CA19-9 as an approach for diagnosis of pancreatic carcinoma.
Serum DNA was extracted from 39 patients with pancreatic carcinoma. Mutation enriched polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to determine codon 12 mutations of K-ras. Serum content of CA19-9 was determined by radioimmunoassay. In addition, the sera from 17 patients with other pancreatic diseases and 21 healthy individuals were also analyzed as control.
K-ras gene mutations at codon 12 were detected in the sera of 71.79%(28/39) patients with pancreatic carcinoma and 11.76%(2/17) of patients with benign pancreatic tumors. The positive rates of CA19-9 were 71.79% and 41.18%, respectively. Parallel combined test increased the diagnostic sensitivity to 94.87%; and serial combined test increased the diagnostic specificity to 94.12%. Negative results of K-ras gene and CA19-9 were obtained in all sera from healthy controls.
Combined detection of K-ras mutation and CA19-9 could increase the sensitivity and specificity in diagnosing pancreatic carcinoma, and would seem to be merited in clinic.