SIRPA and neoplasm: In A549 xenograft model, tumor weight in VEGFR1-Fc group was 426.04 ± 64.26 mg versus 942.20 ± 130.27 mg of the isotype control (P < 0.0001) (Fig. 4a), and the tumor weight in VEGFR1-Fc and SIRPα-Fc co-treatment group was 68.15 ± 35.64 mg (P < 0.0001 versus VEGFR1-Fc group).