Epigenetic alterations in neoplasia.

摘要

In multicellular organisms coregulated expression of gene-sets could either be achieved through repetitive sequences located in the regulatory regions of coexpressed (or cosilenced) promoters or by organizing gene-batteries into higher-order chromosomal structures within interphase nuclei. The establishment of cell identity and cell-type-specific gene expression patterns involves silencing of the majority of genes via epigenetic regulatory mechanisms. Dys-regulation of gene expression due to genetic changes or epigenetic alterations may result in malignant transformation that is either a multistep process, or may happen in a single step as demonstrated in case of certain oncovirus-induced neoplasms. Although this issue focuses on the role of epigenetic dysregulation and epigenetic reprogramming in carcinogenesis and tumor progression, genetic changes (and their epigenetic consequences) are also discussed wherever appropriate.