Method of DNA methylation patterns in CpG islands (or CpG-rich regions of promoter) is crutial as it allows to gather information regarding understanding various biological processes occurring in the cells, for instance, inactivation of X chromosome, regulation of imprinted genes or suppressor gene silencing in tumor cells. Methylation-specific PCR (MSP) is conducted through modification of DNA by sodium bisulfate that converts all unmethylated but not methylated, cytosines (C) to uracil (U) following by amplification with primers that are specific for methylated versus unmethylated DNA. Unlike other PCR-based methods used previously that were replying strictly on differential restriction enzyme cleavage in distinguishing methylated from unmethylated DNA, MSP helps to avoid the false positive results inherent. Thus, MSP is an excellent technique that can be applied in evaluating of the methylation status in CpG island