SET Domain Containing 7: A Tissue-Based Epigenetic Biomarker for Early Detection of Colorectal Cancer.

Background: Methyltransferase proteins, including SET Domain Containing 7 (SETD7), play an important role in the initiation of carcinogenesis through epigenetic mechanisms. Due to the reduced chance of survival in colorectal cancer (CRC), it is necessary to find molecular methods to detect CRC in the early stages. This study aimed to investigate the expression of SETD7 in metastatic and nonmetastatic tumor tissues in CRC compared with healthy tissue in order to evaluate its potential as a biomarker for the diagnosis of CRC in the early stages. Methods: In this study, the expression level of the SETD7 gene in primary colon adenocarcinoma was analyzed using the UALCAN database. To confirm the bioinformatics data, SETD7 gene expression was investigated in 80 colorectal tumor tissues (metastatic and nonmetastatic) and adjacent normal tissues using RT-qPCR. Results: According to the results obtained from the UALCAN database, SETD7 expression is significantly increased in tumor tissues compared with normal tissues, which was confirmed by the RT-qPCR results. We showed that although the SETD7 expression level in colorectal tumor tissues was higher than in adjacent normal tissues (p = 0.0001), this increase was only statistically significant in nonmetastatic tumor tissues (p = 0.0001). Based on receiver operating characteristic (ROC) analysis, increased SETD7 gene expression can be used as a good biomarker to distinguish tumor tissue from normal tissue in the early stages (area under the ROC curve = 0.85). Conclusion: Increased SETD7 gene expression can be used as an epigenetic marker in tissue-based prognosis and screening of CRC in the early tumor stages.