frequent kras mutations and absence of p53 mutations in mucinproducing tumors of the pancreas mucinproducing tumors of the pancreas mpt are characterized by the production of much mucin and a benign course after surgical treatment we examined 16 cases of mpt and 20 cases of common pancreatic duct cell carcinomas dcc in regard to kras and p53 mutations the mutations were detected by constant denaturant gel electrophoresis in combination with other techniques using pcr products amplified from the samples microdissected from the tissue sections kras codon 12 mutations were identified in all mpt and in 95 of dcc on the other hand p53 mutations were found in four of 20 20 dcc and p53 was immunocytochemically overexpressed in 3 of the 4 mutated cases however no p53 mutations and no p53 overexpression were identified in the 16 mpt these results indicate that although the kras codon 12 mutations may be almost essential for the development of both mpt and dcc p53 mutations seemed to be involved mainly to the latters