For example, OAd delivering an EGFR-targeting BiTE (OAd-BiTE) was used to improve the efficacy of folate receptor alpha (FR-α)-specific CAR T-cell therapy by overcoming the problem of tumor heterogeneity in solid tumors.337,338 The cytotoxicity of FR-α-targeted CAR T cells is closely associated with FR-α density. This evidence concerns the gene FOLR1 and neoplasm.