Background: Cholangiocarcinoma (CCA) is one of the most common cancers in Thailand, particularly in north eastern part, where the prevalence of liver fluke infection is high. Mdm2 protein has been characterized as a negative regulator of the tumor suppressor protein p53, which contributes to an increase cancer risk.
Objective: To investigate the expression levels of MDM2 protein and evaluated its association with histopathological grading of CCA patients.
Methods: We performed the immunohistochemistry in 64 formalin-fixed paraffin-embedded (FFPE) tissues of CCA specimens from three hospital medical center in Northeast Thailand. MDM2 protein expression was evaluated by five independent pathologists. Statistical analyses were using the SPSS used for Windows (version 20.0; SPSS, Chicago, IL, USA).The association between MDM2 protein expression and histopathological grading of CCA specimens were evaluated by using logistic regression model. A p-value less than 0.05 were considered as significant.
Results: Histopathologically diagnosed 16 cases of well differentiated adenocarcinoma, 20 cases of moderately differentiated adenocarcinoma and 28 cases of poorly differentiated adenocarcinoma were identified from CCA specimens. MDM2 protein was found to be expressed at high levels in 34 cases of the tumor, while 30 cases were expressed MDM2 protein at low levels. Expression of MDM2 protein at high levels associated with poorly differentiated adenocarcinoma (p<0.01, OR=1.59, 95% CI 1.472-1.713).
Conclusions: Our results indicated that high expression of MDM2 protein in CCA patients is associated with higher histopathological grading of CCA patients in Northeast Thailand. The expression of MDM2 protein characterizes the invasive CCA, which may be of a prognostic value.