The study on the diagnostic and prognostic value of detecting K-ras mutations in plasma of patients with pancreatic cancer by a novel nano capture probe / 中华胰腺病杂志

ABSTRACT

Objective To detect K-ras mutations in plasma by a nano capture probe system , and to explore the diagnostic and prognostic value of this method for patients with pancreatic cancer .Methods The clinical data of 62 patients with pancreatic cancer , 38 patients with benign pancreatic diseases and 31 healthy controls admitted in the Second Affiliated Hospital of Jiaxing Medical College from June 2013 to June 2015 were collected.The diagnosis of all the patients were confirmed by pathology .The DNA were extracted from all plasma samples and were detected for the codon 12 and 13 mutation of K-ras gene by nano capture probe and conventional PCR plus direct sequencing .The correlation of K-ras gene mutation with certain clinical data and the diagnostic and prognostic value in pancreatic cancer were analyzed .Results The K-ras mutation were detected by nano capture probe in 27 pancreatic cancer patients , and the mutation rate was 43.5%(27/62), including 25 cases with codon 12 mutation and 2 cases with codon 13 mutation .The K-ras mutation rate in patients with benign pancreatic diseases was 7.9%(3/38), which were all in codon 12.K-ras mutation was detected in only 17 pancreatic cancer patients by conventional PCR plus direct sequencing , and the mutation rate was 27.4%(17/62), The K-ras mutation rate of benign pancreatic diseases was 5.3%(2/38).The mutation rate detected by nano capture probe was higher than that by conventional PCR , and the difference was statistically significant (P=0.006).K-ras mutation in the plasma of patients with pancreatic cancer was related to TMN stage and liver metastasis , but there was no correlation of the factors such as sex , age, clinical symptoms, tumor size, serum CA19-9 and CEA levels with K-ras mutation.The sensitivity of K-ras gene mutation for diagnosing pancreatic cancer was 43.5%, the specificity was 92.1%, the positive predictive value was 90%, the negative predictive value was 50%, Youden index was 0.356.The 1-year survival rate of patients with K-ras mutation was 44.4%, which was lower than that (71.4%) of patients with wild-type K-ras, and the difference was statistically significant (P<0.05).Conclusions The nano capture probe system could certainly detect K-ras mutation in a small quantity of plasma DNA , and its diagnosis sensitivity for pancreatic cancer is low , but the specificity is relatively high .K-ras mutation in plasma is closely related to the TMN stage and prognosis of pancreatic cancer .