Methylation Facilitates Tumor Progression - Brief Article

Applied Genetics News, April, 2000

DNA methylation is normally a means used by cells to turn off the expression of genes that are needed. Inappropriate methylation has been now been found to facilitate cancer progression. The research was led by Christopher Plass, assistant professor at the Ohio State University Comprehensive Cancer, and published in Nature Genetics.

"We thought we understood tumor progression," says Plass, "Now there is this second layer of complexity. A lot of scientists are going to be kept very busy trying to understand this." The researchers had expected that a few tumor suppressor genes might be inactivated by methylation. Instead, they found that up to 10% of the genes in some tumors types were methylated and presumably not expressed.

The researchers also found that the pattern of methylation was very specific for certain kinds of cancer. "This aberrant methylation doesn't occur at random," says Plass. "In some tumor types--leukemia and head and neck cancer, for example--certain genes are methylated in very specific places, and we can use those sites as markers for certain tumor types." Preliminary evidence suggests that resistance to chemotherapy is in some cases linked to the degree of aberrant methylation in tumors.