Methylated CpG Island Amplification for Methylation Analysis and Cloning Differentially Methylated Sequences

CpG islands are clusters of CpG dinucleotides that can be found in the 5′ region of about half of human genes (1 ). Methylation of cytosine within the 5′ CpG islands is associated with transcriptional inactivation of the involved gene. Aberrant methylation of CpG islands is an important mechanism of gene inactivation in cancer (2 ,3 ) and other states such as aging and age-related diseases (4 ). Such methylation often involves numerous CpG islands, and emerging data suggests that methylation profiles may be of some utility in disease detection, prognosis, and risk assessment. However, the measurement of DNA methylation abnormalities at multiple gene loci is currently cumbersome, time-consuming, and not easily amenable to automation. Furthermore, the identification of novel gene sequences hypermethylated in cancer is relatively difficult and inefficient using current technology (5 ,6 ). Methylated CpG island Amplification (MCA) was developed to overcome these problems (7 ).