High potential of SOX21 gene promoter methylation as an epigenetic biomarker for early detection of colorectal cancer.

Despite the advances in screening during the past decades, colorectal cancer (CRC) still is a leading cause of cancer deaths worldwide. Therefore, the development of new diagnostic methods is necessary.The aim of this study was to compare methylation changes of SRY-Box 21 (SOX21) gene promoter in tumor tissues and their normal adjacent mucosa in patients with CRC and to examine the relationship between the methylation levels and demographic/clinicopathological factors.A total of 41 CRC patients participated in the present study. After the extraction of DNA and bisulfite treatment of the samples, the methylation levels were determined by using the MethyLight method.Two-sided Mann-Whitney U test was used to compare the median level of methylation in tumor tissues and their adjacent normal mucosa.The methylation rates in tumor tissue samples were significantly higher compared to their adjacent normal mucosa (P < 0.0001). No association between demographic/clinicopathological factors and methylation status observed in tumor tissues. A receiver operating characteristics curve was constructed and tissue samples exhibited a sensitivity of 80.5% and specificity of 97.6% for SOX21 promoter methylation.The results of this study indicated the high potential of SOX21 gene promoter methylation as a candidate noninvasive diagnostic biomarker in stool and plasma of colorectal cancer patients. However, further studies with larger sample sizes are required to evaluate the specific role of SOX21 methylation as a biomarker for early detection of CRC.