Diagnosis of pancreatic cancer by K-ras point mutation and cytology of pancreatic juice

Abstract

Objectives: Recently, it was reported that detection of K-ras point mutation at codon 12 in pancreatic juice is an objective method for the diagnosis of pancreatic cancer, but a few reports have suggested that this might represent an early event in pancreatic oncogenesis. In the present study we examined, in various patients, the occurrence of K-ras codon 12 point mutation in pancreatic juice and compared it with pancreatic juice cytology, which is also a reliable diagnostic method.

Methods: Pancreatic juice was obtained endoscopically from patients with various pancreatic disorders and those without definite diseases, and was examined cytologically and for the occurrence of K-ras codon 12 point mutation. The K-ras gene was amplified by polymerase chain reaction (PCR) and the mutation at codon 12 (GGT-->GAT) was examined by slot blot hybridization analysis.

Results: K-ras point mutation at codon 12 was detected in seven of 14 (50%) pancreatic cancers, in four of 10 (40%) mucin-producing tumors, in four of 13 (31%) chronic pancreatitis, and in two of 10 (20%) pancreas without definite disorders. K-ras point mutation was detected in nine of 18 (50%) pancreatic juice samples containing cancer cells, in eight of 18 (44%) pancreatic juice samples containing atypical cells, but in none of such samples containing only normal cells.

Conclusion: Cancer cells were detected from pancreatic cancer exclusively, but K-ras point mutation at codon 12 was detected in pancreatic juice, not only from pancreatic cancer, but also from other diseases.