Analysis of K-ras codon 12 point mutations using duodenal lavage fluid for diagnosis of pancreatic carcinoma

We evaluated the diagnostic significance of the K-ras point mutations at codon 12 in duodenal lavage fluid (DLF) compared with pure pancreatic juice (PPJ). The DLF was easily and safely collected by injecting distilled water into the duodenum and then aspirating through the working channel of the endoscope during endoscopic retrograde cholangiopancreatography. Two types of DLF are collected this way: DLF 1 is collected just after insertion of the endoscope into the duodenum and DLF 2 is collected after cholangiopancreatography and/or collection of the PPJ using secretin. Analysis of K-ras mutations was performed using enriched polymerase chain reaction. In patients with pancreatic carcinoma (PC), K-ras mutations were detected in 14 of 23 (60.9%) in DLF 1, 16 of 21 (76.2%) in DLF 2, 14 of 20 (70.0%) in PPJ, and 19 of 21 (90.5%) in either DLF 1 or DLF 2. In patients with noncancerous pancreatic diseases consisting of pancreatic cystic diseases and chronic pancreatitis, the incidence of K-ras mutations was 2 of 21 (9.5%) in DLF 1 and 7 of 19 (36.8%) in DLF 2. These values were lower than that in PPJ, and there was significant difference between the incidence in DLF 1 and PPJ. These results suggested that DLF may provide a new and useful material for analysis of K-ras codon 12 point mutations in the diagnosis of PC.