To address the role of PI3K and AKT isoforms in controlling clonogenic survival, we first identified concentrations of p110α, p110β, AKT1 and AKT2 inhibitors that had minimal effect on the 2D proliferation of PC lines but were significantly above the IC50’s reported for each drug (examples in Supplementary Figs. S2E & S4D). This evidence concerns the gene PIK3CD and pachyonychia congenita.