ITGAM and neoplasm: Once recruited to the tumor, monocyte progenitors (CD11b+ SiglecF− Ly-6G−Ly6C+ F4/80− CD169− MHC-II−) undergo a multistep differentiation program [13,14], passing through an immature stage (Ly6C+ F4/80− CD169int MHC-IIhi) before reaching a mature state (Ly6C− F4/80+ CD169hi MHC-IIhi or low).