CpG island methylation of the CADM1 gene correlates with cervical carcinogenesis in the Uighur and Han populations of Xinjiang, China

Aberrant DNA hypermethylation in gene promoter regions is one of most well-fined epigenetic alterations in tumors and is associated with gene silencing. Cell adhesion molecule 1 (CADM1), an immunoglobulin, could lead to tumor invasion or metastasis with the inhibition of gene expression mainly induced by promoter methylation. We used a MassARRAY platform to test methylation of 10 CpG sites in the promoter region of the CADM1 gene and used MALDI-TOF mass spectrometry to draw the gene mass spectrogram. HPV16 infection was detected by PCR. Results showed a trend of the methylation rate of the CADM1 gene promoter increasing with severity of the disease, and aberrant methylation of CADM1 was present in a higher proportion of invasive cervical carcinoma (ICC) clinical samples compared with normal samples in Uighurs and Han populations. Among the four pathologic lesions formed during the progression of cervical cancer, ICC showed the highest methylation rate and a stronger correlation between CpG sites and lesion grades in Uighurs than in Hans. Methylation of specific CpG sites in the CADM1 gene promoter region was observed between HPV16-positive and -negative groups. Altogether, these results indicate that DNA methylation of CADM1 may play an important role in the carcinogenesis of cervical cancer, and the differential methylation of CADM1 may partially explain the disparity in cervical cancer incidence between Uighur and Han women.