In summary, we have identified INPP4B as an oncogenic driver that promotes melanoma cell proliferation independently of Akt through activation of PI3K/SGK3 signalling, and revealed loss of miR-494 and miR-599 due to gene copy number reduction as the mechanism responsible for upregulation of INPP4B in a subset of melanomas (Supplementary Figure 8). Here, SGK3 is linked to melanoma.