PTEN and melanoma: Given our previous data suggesting that E6201 resistance is associated with mutation of PTEN and high levels of pAkt, we hypothesized that combining E6201 with an inhibitor of the PI3K pathway in these cell lines might result in either an additive or synergistic effect.Additional file 2: Figure S2 demonstrates that LY294002 effectively inhibits PI3K by evidence of reduced phosphorylated AKT protein levels in the four PTEN-mutant melanoma cell lines that normally express high levels of pAKT (UACC647, UACC558, UACC903 and MM622).