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-res 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-res. 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.