MAP3K1 and neoplasm: SPP1 in humans and Spp1 in mice encodes for a multifunctional phosphoglycoprotein (osteopontin, OPN) secreted by various tumor‐associated cells, mostly TAM and tumor cells.[10] Three major OPN receptor‐interacting receptors activate overlapping oncogenic signaling pathways, including hypoxia‐inducible factor 2a (HIF2a), alpha‐v beta‐3 integrin (avB3; MEKK1), and alpha‐4 beta‐1 integrin (IKK, AKT, Ras).