AKT1 and cancer: The closely related isoforms AKT1 and AKT2 are evidently co-expressed with AKT3, but they cannot fully compensate for loss of AKT3, suggesting that either AKT3 is preferentially used by these cell lines to relay upstream signals or that AKT3 fulfils a unique role in CMS4 mesenchymal cancer cells that cannot be compensated for by AKT1/2.