ICAM1 and neoplasm: The mitogen-activated protein kinase (MAPK) signaling pathway has been reported to manipulate phagocytosis.42, 43 To elucidate whether the MAPK signaling pathway is involved in the enhanced phagocytic activities of ICAM-1−/− macrophages, we studied the activation of several MAPKs and monitored apoptotic tumor cell phagocytosis.