EXPRESSION OF PANCREATITIS-ASSOCIATED PROTEIN (PAP) MESSENGER-RNA IN GASTROINTESTINAL CANCERS

Conclusion, Pancreatitis-associated protein (PAP) mRNA is expressed in some cases of gastric and colorectal cancers resulting from an ectopi c expression in dedifferentiated cancer cells, Background, The PAP gen e is identical to the hepatoma-intestine-pancreas (HIP) gene, which is expressed in hepatoma. Expression in cancer might be another characte ristic of PAP. Methods, Fresh surgical specimens of 100 gastrointestin al cancers, 14 benign digestive diseases, and six normal organs were s tudied with nonisotopic in situ hybridization (ISH) using biotin-label ed cDNA probe. Results, PAP mRNA was detected in 10% (6/60) of gastric cancers, 21.4% (6/28) of colorectal cancers, 20.0% (1/5) of pancreati c cancers and 0% of biliary tract (three), esophageal (one), and hepat ocellular cancers (three). Reverse transcription-polymerase chain reac tion (RT-PCR) detected PAP mRNA in these ISH-positive cases. PAP mRNA was not detected in noncancerous portions, benign disease tissues, or normal organs except for the small intestine. There was no relationshi p between PAP mRNA expression and any clinicopathological factors.