TFRC and leukemia: According to the biological functions of surface antigen, we divide leukemia surface antigens into three categories: (1) metabolism-related antigens, such as CD71 [202], FA receptor [203], PTK7 [204]; (2) immune antigens, such as CD19 [58, 205, 206], CD3 [207], CD33 [128, 208], B220 [209], CD117 [210], CD123 [211] and IL-1RAP [212], and (3) cell adhesion or migration-associated antigens, such as ITGB2 [93], CXCR4 [213] and CD44 [64].