Absence of K-ras mutations in the pancreatic parenchyma of patients with chronic pancreatitis

Background Human pancreatic cancers exhibit a high frequency of K-ras mutations. Methods In this study we used oligonucleotide specific hybridization to compare the frequency of K-ras mutations in genomic DNA samples prepared from 21 normal pancreatic tissues, 26 chronic pancreatitis tissues, and 24 pancreatic cancers. Results None of the DNA samples from normal or chronic pancreatitis tissues exhibited a K-ras mutation at codons 12 or 13 of K-ras. In contrast, 17 of 24 DNA pancreatic cancers harbored a K-ras mutation. Validity of the methodology was confirmed by genotyping 7 human pancreatic cancer cell lines. Analysis of focal areas of proliferation from 5 chronic pancreatitis and 5 pancreatic cancer samples processed by selective ultraviolet radiation fractionation (SURF), a procedure used to enrich DNA isolation from foci of proliferating cells, revealed complete concordance with total genomic DNA analysis. Conclusions These findings indicate that the pancreatic parenchyma in patients with chronic pancreatitis most frequently does not possess a K-ras mutation.