SIRPA and neoplasm: Two rounds of treatment comprising 8 Gy RT and i.t. infusion of Sirpα−/− BMDMs, which achieves an equal quantity of intratumoral Sirpα−/− BMDM and endogenous intratumoral WT macrophages (~1 × 104 cells per mm3 of tumor volume), led to complete regression of MC38 tumors larger than 200 mm3 in WT mice and 100% survival rates.