Orlando—Before any perceptible signs
of disease, even before a single tumor cell divides and starts a malignant
cascade, the first event that leads to cancer is a change in gene expression.
Scientists have discovered many cases in which mutations in the DNA sequence—such
as point mutations or deletions—alter gene expression and set the stage
But as scientists strive to decipher which genetic changes can make
cells cancerous, they are also discovering that not all such changes involve
mutations that alter the DNA sequence. Rather, some are a result of "epigenetic"
modifications, heritable changes in gene function that occur without any mutation
in gene sequence.
Hampton T. Scientists Probe Shutting Down Cancer Cells by Awakening Silenced Genes. JAMA. 2004;291(19):2301-2305. doi:10.1001/jama.291.19.2301