LY9 and neoplasm: As known, phagocytosis of tumor cells by macrophages is an important mechanism of antitumor immunity.[13, 39, 40, 41] SLAMF3 has been reported as a “don't eat me” immune checkpoint that constrains macrophage phagocytosis of hematopoietic tumors,[42] but SLAMF3 role in CRLM remains unclear.