COMT Expression Increases In Human Colorectal Adenomas And Carcinomas And Is Correlated With TNM Stage And Tumor Dedifferentiation

Purpose:To explore the dynamic expression of COMT (catechol-O-methyl transferase) in colorectal adenomas, carcinomas and adjacent mucosal tissues. To determine the correlation between COMT expression and clinicopathologic parameters of colorectal cancer (CRC).Methods:COMT expression was evaluated in 49 pairs of colorectal adenomas/adjacent tissues and 42 pairs of CRCs/adjacent tissues using qRT-PCR and immunohistochemistry. COMT expression in another 81 CRC cases was assessed using immunohistochemistry. Differences between groups were analyzed using a paired/independent t-test with SPSS 13.0 software.Results:Both COMT mRNA and protein expression were higher in colorectal adenomas than in adjacent mucosae (P=0.011 and P=0.000, respectively). Similarly, expression of COMT mRNA and protein was significantly higher in CRCs than in adjacent noncancerous mucosae (P=0.007 and P=0.000, respectively). Furthermore, COMT protein expression was not significantly different between colorectal adenomas and early T/N/TNM stage CRCs (P=0.933, P=0.527, P=0.227, respectively), while it was lower in advanced T/N/TNM stage CRCs compared with early stage cases (P=0.018, P=0.000, P=0.000, respectively). There was also no obvious difference between COMT expression in adenomas and that highly/moderately differentiated cases (P=0.153). However, COMT expression was lower in poorly differentiated carcinomas compared than in highly/moderately differentiated cases (P=0.005).Conclusions:This study is the first to investigate COMT dynamic expression in colorectal adenomas and carcinomas. Our results support suggestions that COMT might be implicated in the process linked to the genesis of colorectal adenomas and carcinomas, and may be associated with the dedifferentiation and T/N/TNM stage of CRC. Therefore, it might serve as a potential biomarker for diagnosis, stage and differentiation of CRC.