Detection of K- ras mutations in the plasma DNA of pancreatic cancer patients

Background  In pancreatic cancers, K-ras mutations have been found frequently (80%–100%), and they could be a good marker to detect tumor DNA in the plasma. Several studies have indicated that polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analysis of K-ras mutation was a useful method for the detection of hepatic and lymph node metastasis of pancreatic cancer. However, this method sometimes exhibited false-positive results, and the rate of K-ras mutation might thus be overestimated in these tissues. To diagnose pancreatic cancer correctly at an early stage, we attempted to detect tumor DNA in the plasma of pancreatic cancer patients using a more sensitive and specific method.Methods  We examined 28 pancreatic cancer patients using a sensitive mutation-specific mismatch ligation assay for K-ras gene mutations in primary tumors and paired plasma samples.