To further verify the ability of pep-20 to block CD47/SIRPα interaction, the SIRPα tyrosine residues phosphorylation with pep-20 intervention was evaluated.24 As a negative regulation signal of CD47/SIRPα axis, the ligation of SIRPα by CD47 could lead to tyrosine phosphorylation of immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in its cytoplasmic domain.25 For the validity of the experimental results, SIRPα expression on several murine tumor cells was evaluated and it was found that SIRPα was not detected on CT26 cells. This evidence concerns the gene CD47 and neoplasm.