In another study, Barkal et al. verified that cancer cells could express MHC class I component β2-microglobulin (β2M) on their surface and β2M could bind with leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1), which exists on the surfaces of TAMs, subsequently protecting cancer cells from the phagocytosis of TAMs [169]. This evidence concerns the gene B2M and cancer.