SEMA3A and neoplasm: This pro-tumoural function of hypoxic TAMs was validated by Casazza et al, wherein they showed that macrophage-specific genetic deletion of Nrp-1, a binding partner of hypoxia induced TAM attractant Semaphorin 3A (Sema3A), prevented macrophage entry into the hypoxic region and ablated pro-angiogenic and immunosuppressive functions of TAMs, thereby inhibiting tumour growth and metastasis (Casazza et al, 2013).