NCIt definition : This process is initiated by the formation of heterochromatin which ultimately leads
to transcriptional inactivation or silencing. Once formed, heterochromatin can be
inherited through many cell divisions, including meiosis. Inappropriate gain of heterochromatin
structure, such as the inactivation of tumor suppressor genes by DNA hyper-methylation
at their promoter regions, can be directly linked to carcinogenesis.;