SPP1 and neoplasm: The co-variation of SPP1 and chemokines along the pseudotime suggests that SPP1+TAMs are macrophages that might develop from monocytes that are recruited into tumor regions and undergo reprogramming via chemotaxis; therefore, targeting this biological process is expected to significantly repress the expansion and differentiation of TAMs, thus reducing the formation of a tumor-inhibiting microenvironment [44].