FLT1 and neoplasm: The evaluation of the anti-tumor effects of SIRPα-VEGFR1, a bispecific fusion protein that concurrently inhibits CD47 and VEGF, demonstrated significant tumor regression in the Hu-PDX1 model, comparable to the observed effects in the SIRPα-Fc + VEGFR1-Fc combination group (Fig. 6A, B).