Evaluation of MALAT1 promoter DNA methylation patterns in early colorectal lesions and tumors

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is one of the long non-coding RNAs that plays an important role in invasion, cell proliferation and metastasis of various cancers. However, insufficient information on the association of MALAT1 with the methylation process and its role in the development of colorectal cancer is not yet fully available. This study set out to determine the effect of methylation on MALAT1 gene in primary colorectal lesions and tumors to gain further knowledge about the diagnostic and prognostic value of MALAT1.

Methylation Pattern of MALAT1 promoter determined by Methylation-Specific Polymerase Chain Reaction (MSP) in 86 colorectal primary lesions, tumors and normal specimens. MALAT1 methylation pattern was compared in tumor and polyp tissue. In order to obtain more accurate results, we investigated the association of MALAT1 promoter methylation pattern with clinicopathologic factors in patients.

The results indicated that the MALAT1 promoter methylation pattern in tumor tissue, primary lesions tissue and normal was not significant difference (p=0.430). Moreover, compared, the MALAT1 promoter methylation pattern between polyp types and tumor tissue groups was not significant (p=0.437). Surprisingly, the methylation frequency of MALAT1 methylation was significantly higher in colon lesions in comparison with their rectum lesion, p = 0.035. In addition, significant hypermethylation of MALAT1 was not observed between the other patients’ clinicopathological data at both polyps 46/66 and tumor tissue 20/66.

This study suggests that the MALAT1 promoter methylation pattern in patients with colorectal primary lesions and tumors compared with normal tissue as not a significant risk factor for colorectal cancer. Moreover, clearance the significantly higher methylation frequency in colon lesions in comparison with their rectum lesion need to be further explored.