Studies in primary and tumor cells suggest that MYC plays an important role in 
regulating cellular senescence, thereby impacting on tumor development. Here we 
describe different common methods to measure senescence in cell cultures and in 
tissues. These include measurement of senescence-associated β-galactosidase 
activity (SA-β-gal), senescence-associated heterochromatin foci (SAHFs), 
proliferative arrest, morphological changes, and expression and activity of 
proteins involved in the senescence process, such as p53 and Rb pathway proteins 
and secretory proteins. It is important to note that there is no unique marker 
that unambiguously defines a senescent state, and it is therefore necessary to 
combine measurements of several different markers that together determine 
whether cells are senescent or not. Measurement of senescence is an important 
aspect of studies of MYC biology and will improve our understanding of MYC 
function and regulation both in preclinical and clinical settings. This may form 
the basis for new concepts of pro-senescence therapy to combat MYC in cancer.