BACKGROUND/AIMS: The Ki-ras gene located at 12p, encodes the GTP binding pr
otein involving the signal transduction system and concerns cell proliferat
ion and differentiation.
METHODOLOGY: Pancreatic tissues were obtained from 37 patients with various
pancreatic diseases. Ki-ras codon 12 point mutation and p53 (exon 5-8) mut
ation were examined in 3 patients with chronic pancreatitis, 9 mucinous ade
noma of the pancreas (2 with mucinous cystadenoma and 7 with intraductal pa
pillary-mucinous adenoma), 22 pancreatic ductal carcinoma, and 3 serous cys
tadenoma.
RESULTS: On usual pancreatic exocrine ductal lesions, Ki-ras point mutation
was evident in 0% (0/3) of chronic pancreatitis, in 56% (5/9) of mucinous
adenoma, and in 57% (12/21) of ductal carcinoma, the mutation being located
in the second letter in 18 and in the Ist letter in 2. One Ki-ras codon 12
positive pancreatic cancer showed Ki-ras codon 12 point mutation in the su
rrounding pancreas (2nd letter mutation in both areas), p53 mutation was pr
esent in 0% (0/1) of chronic pancreatitis, in 0% (0/8) of mucinous adenoma,
while it was evident in 29% (6/21) of pancreatic ductal carcinoma, the mut
ation being situated in exon 5 in 3, in exon 6 in 1, and in exon 7 in 2. In
3 patients with serous cystadenoma, there was no mutation in Ki-ras codon
12 or p53 (exon 5-8).
CONCLUSIONS: These findings suggest that Ki-ras point mutation is involved
in the early events of pancreatic ductal carcinoma, while p53 mutation is i
ntricated in the late phase of pancreatic ductal carcinogenesis and the his
togenesis of serous cystadenoma is different from that of pancreatic exocri
ne ductal lesions including mucinous adenoma and ductal carcinoma.