B2M and cancer: Cancer cells evade clearance by macrophages via overexpressing the anti-phagocytic membrane proteins termed “don’t eat me” signals, including cluster of differentiation 47 (CD47),7 cluster of differentiation 24 (CD24),8 PD-L1,9 the beta-2 microglobulin (β2M) subunit of the major histocompatibility class I complex (MHC-I),10 stanniocalcin 1 (STC-1),11 and GD212 (Figs. 1, 2).