Microsatellite instability

Genetic perturbation has been implicated in the development of tumours since the turn of the century. Indeed, genetic instability of one sort or another may be considered to be a hallmark of cancer itself, and the discovery of microsatellite instability (MSI) made it evident that there was more than one mechanism underlying this process. 1 2 As with most new discoveries, there was an initial flurry of excitement with raised hopes and exaggerated claims, followed by the realisation that MSI was not as simple, easy, or likely to give results as had first been thought. The understanding of MSI and its potential clinical utility has continued to develop, but it is only now that its real usefulness is becoming apparent.