Our study shows the prognostic significance of MK-1 and RegIV expression as a tumor biological marker in patients with gallbladder adenocarcinoma. We found that positive expression rate of MK-1 and RegIV were higher in gallbladder adenocarcinoma than those in peritumoral tissues, polyp and chronic cholecystitis. Statisitical analysis revealed that MK-1 negative expression and RegIV positive expression is negatively correlated with mean survival time after surgery, positively correlated with mortality, and are independent prognostic markers.
The expression of MK-1 has been previously reported in several carcinomas. In gastric carcinomas, MK-1 is more frequently expressed in cardiac tumors (with 50% expression rate), in large (> 3 cm) tumors, and in specimens from patients with more than five metastatic lymph nodes . In urinary bladder carcinoma, 56.8% were positive for MK-1 protein expression and significant correlations were observed between MK-1 expression and tumor grade, schistosoma, DNA ploidy and tumor recurrence . In Gallbladder carcinoma, expression of MK-1 was found in 50 (79%) of 63 tumor samples. Multivariate analysis showed that MK-1 expression was an independent prognostic marker, and Kaplan-Meier curves showed that MK-1 expression was significantly related to increased overall survival, suggesting that MK-1 expression is a prognostic marker in gallbladder carcinoma . In our study the positive expression rate of MK-1 was slightly lower than what was previously reported (62% vs 79%), however, our statistical analysis revealed similar prognostic significance of MK-1 expression.
The expression of RegIV has also been reported to be increased in some carcinomas including prostate, pancreatic and gastric cancer [6–11]. The expression of RegIV has been found to be related to the carcinogenesis, clinical biological behaviors, and prognosis of the carcinomas studied. Most of the high RegIV cases have poorly differentiated, high clinical stage, prone to metastasis and strong invasion ability, which are all considered being bad indicators of cancer prognosis [6–11, 16]. These results all support that RegIV may involve in cancer formation and affect its development and prognosis. To the best of our knowledge our study is the first of RegIV expression in gallbladder adenocarcinoma. We showed that the positive expression of RegIV in gallbladder adenocarcinoma samples was significantly higher than in benign gallbladder lesions. In adenocarcinomas, MK-1 positive expression rate was significantly higher in samples that were highly differentiated, with tumor diameter < 2 cm, with no lymph node metastasis and no peritissue invasion. Moreover, RegIV positive expression was negatively correlated with mean survival time after surgery, positively correlated with mortality, and are independent prognostic markers. These findings indicate that RegIV is a promising tumor marker in gallbladder adenocarcinoma.