MAP4K1 and melanoma: To assess the impact of HPK1 deficiency on melanoma metastasis, we compared the metastatic susceptibility of MAP4K1 KO and WT control mice after intravenous injection of B16F10 cells, of which host control is primarily mediated by NK cells.[16, 25]MAP4K1 KO mice were significantly and highly resistant to experimental metastasis than WT control mice in the lung and other organs on day 12 when challenged with B16F10 cells, as opposed to Ncr1iCreMAP4K1Tg mice (Figure 5a,b).