Gene signature
Cancer is a multistep process, with many genes (and environmental factors) being involved. Although the same type of cancer from several patients may have the same appearance down the microscope, each may have different genes involved in its causation, or the same genes but with different changes in them. These changes are likely to affect how the genes involved are expressed - they may be made "more active", "less active" or completely inactivated. This is called an alteration of gene expression. Different patterns of gene involvement may respond better to some therapies than other patterns and research is trying to identify these.
Microarray technology now allows the simultaneous screening of gene expression patterns on a genome-wide scale - sometimes called a "gene profile" or "gene signatures". As well as increasing our understanding of the causes of tumours, these patterns may then be used to develop statistical models of association with disease subtype, disease prognoses and response to therapies, including targetted drugs.
