BACKGROUND:Regulatory peptide receptors have attracted the interest of oncologists as a new promising approach for cancer pathology,imaging and therapy.Although cholecystokinin (CCK) is a potent modulator of gallbladder contractility and plays a potential role in pancreatic carcinogenesis through CCK type-A receptor (CCKAR),its role in gallbladder cancer (GBC) is still unknown and immunohistochemical detection of CCKAR in the gallbladder has not yet been reported.This novel case-control study aimed to investigate the expression profile of CCKAR in GBC and gallstone disease (GSD).METHODS:This study included 162 samples of gallbladder:94 from GBC and 68 from GSD.Expression of CCKAR was analyzed by immunohistochemistry and immunoblotting.The results were statistically correlated with disease history including age,sex,presence of gallstone,stage and differentiation.RESULTS:CCKAR was positive in 30/68 (44.1%) of GSD and 72/94 (76.6%) of GBC samples.Fifty-one of the 72 (70.8%) CCKAR-positive GBC samples showed over-expression.Interestingly,consistent results also appeared in the immunoblotting study.CONCLUSIONS:CCKAR expression was significantly increased in GBC compared to GSD.Moreover,CCKAR expression was associated with the degree of tumor differentiation,i.e.,less expression in poorly-differentiated tumors.Thus,it has future prognostic and therapeutic implications in the management of GBC. BACKGROUND: Regulatory peptide receptors have attracted the interest of oncologists as a new promising approach for cancer pathology, imaging and therapy. Although cholecystokinin (CCK) is a potent modulator of gallbladder contractility and plays a potential role in pancreatic carcinogenesis through CCK type-A receptor (CCKAR), its role in gallbladder cancer (GBC) is still unknown and immunohistochemical detection of CCKAR in the gallbladder has not yet been reported. This novel case-control study aimed to investigate the expression profile of CCKAR in GBC and gallstone disease (GSD ) .METHODS: This study included 162 samples of gallbladder: 94 from GBC and 68 from GSD. Expression of CCKAR was analyzed by immunohistochemistry and immunoblotting.The results were statistically correlated with disease history including age, sex, presence of gallstone, stage and differentiation . RESULTS: CCKAR was positive in 30/68 (44.1%) of GSD and 72/94 (76.6%) of GBC samples.Fifty-one of the 72 (70.8%) CCKAR-positive GBC samples showed over-expression. Interestingly, consistent results also appeared in the immunoblotting study. CONCLUSIONS: CCKAR expression was significantly increased in GBC compared to GSD. Moreover, CCKAR expression was associated with the degree of tumor differentiation, ie, less expression in poorly -differentiated tumors.Thus, it has future prognostic and therapeutic implications in the management of GBC.