The study of the relationship between clinical stage, or prognostic and kirsten rat sarcoma viral oncogene mutations of patients with pancreatic cancer detected by a nano probe

Abstract

Objective To establish a method of detection kirsten rat sarcoma viral oncogene mutations in plasma by a nano capture probe system, and to explore the relationship between clinical pathology stage, or prognostic and K-ras single nucleotide polymorphism mutations in patients with pancreatic cancer. Methods The plasma samples of 72 patients with pancreatic cancer were collected from June 2013 to September 2015. The diagnosis of all patients were explicit. 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. The relationship between clinical pathology factors, or prognostic and K-ras point mutations in pancreatic cancer was analyzed via clinical data. Results The plasma DNA concentration of 72 patients with pancreatic cancer was 20-200 ng/μl, 33 patients were detected for K-ras gene mutation, the cycle threshold (Ct) value was 21.71-35.61, including 30 patients for codon 12 mutation and 3 patients for codon 13 mutation, the K-ras mutation rate was 45.8% (33/72). 10 of 37 patients with early pancreatic cancer (stage Ⅰ and Ⅱ) were detected for K-ras gene mutation, the mutation rate was 27.0% (10/37), but 23 of 35 patients with advanced pancreatic cancer (stage Ⅲ and Ⅳ) were detected for K-ras gene mutation, the mutation rate was 65.7% (23/35), the difference is statistically significant (χ2=10.843, P=0.001), it is suggested that K-ras mutation in plasma is ralated to tumor stage. All 72 patients with pancreatic cancer were followed up, the follow-up time was 2 months to 26 months, the average follow-up time was 9.7 months. The one-year survival rate of patients with K-ras mutation is 42.6%, and the one-year survival rate of patients with wild genotype is 73.4%, the difference is statistically significant (χ2=5.335, P=0.017)). Conclusion The nano capture probe system could certainly detect K-ras mutation in rare plasma DNA. K-ras mutation in plasma is related to TMN stage and prognosis of pancreatic cancer, and K-ras mutation in plasma DNA is a predictive biomarker for a poor prognosis of pancreatic cancer patients. Key words: Pancreatic cancer; Prognosis; Mutation; Magnetic nanoparticles