In situ injection of antitumour drugs is a practical strategy for cancer immunotherapy [21, 22]; in situ injection of CpG increases the expression of OX40 on CD4+ T cells in the tumour microenvironment, and the agonistic antibody OX40 triggers the immune response mediated by T cells and produces a systemic antitumour effect. This evidence concerns the gene CD4 and neoplasm.