In China, researchers used naked plasmids to deliver sPD-1-CH50 into tumor inoculation sites and found that sPD-1-CH50 stimulates more effective antitumor activity than sPD-1, CH50 or sPD-1/CH50, which shows that the recombinant protein sPD-1-CH50 can be used as a therapeutic strategy after the surgical removal of tumors [26]. This evidence concerns the gene HOXD13 and neoplasm.