AKT3 and melanoma: Further, neither the TUMM nor SM1-750 cells showed AKT2 phosphorylation in low-attachment cell culture plates or in the primary tumors produced following subcutaneous injection into NOD/SCID mice (Supplementary Figure S3D,E), indicating that while AKT1 or AKT3 phosphorylation can drive melanoma cell growth and primary tumor formation, the activation of AKT2 correlates strongly with an ability to grow in the metastatic niche.