EPS8 and cancer: EPS8 was first identified almost three decades ago,20,49 yet relatively little is known about how it is regulated to mediate its downstream signalling functions, although it has previously been reported to be constitutively tyrosine phosphorylated in some cancer cells,23 including those transformed by v-src.38 In this study, therefore, we investigated the impact of blocking four tyrosine residues within EPS8, previously reported as targets for Src activity,30 on the expression of downstream mediators of the cell cycle and associated biological properties.