Non-invasive detection of aberrant DNA methylation in colorectal cancer by multiplex methylation specific PCR

Colorectal cancer (CRC) is a leading cause of morbidity and mortality worldwide, with an increasing prevalence. The 5-year relative survival rate for advanced stages is very low, with only 14% for stage IV. However, that of the early stage of CRC is about 90%. Therefore, it is important to screen CRC in the early stage. Epigenetic alterations linked to the carcinogenesis of CRC have been shown to occur earlier and more frequently than genetic alterations in CRC. Here, our study aims to develop a CRC screening methodology by applying the multiplex methylation specific PCR (MMSP) assay to detect CRC-specific methylation biomarkers, which has been pre-selected from public databases and subsequently validated in CRC samples of the Chinese population. Experimentally, cell free DNA (cfDNA) is extracted from ~4ml peripheral blood plasma. Following bisulfite conversion of the cfDNA, MMSP were applied to amplify and detect CRC-specific methylated CpG sites within the cfDNA. From the results of 28 CRCs and 52 control specimens, a sensitivity of 85.7% and the a specificity of 92.3% was achieved. Current standard and most widely used method of detecting CRC is colonoscopy screening. However, colonoscopy requires bowel preparation, and the sedation for patients is a complex and time-consuming procedure with high cost. Additionally, this invasive method also increases the possibility of infection and complications and patient compliance still largely remains a problem. Our non-invasive MMSP assay therefore provides an alternative non-invasive screening option that is cost-effective, meeting the urgent demand of early CRC detection. In addition, because colonoscopy screening currently has low adherence in Chinese population, our method holds great potential for increasing CRC screening rate in China. Citation Format: Lili Ye, Chunting Zheng, Yuan Jie, Bin Li, Yuan Li, Kunling Hu, Liuhong Zeng, Yuying Wang, Mao Mao, Peirong Ding, Taiping Shi, Mingzhi Ye. Non-invasive detection of aberrant DNA methylation in colorectal cancer by multiplex methylation specific PCR [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3324.