Sensitive CAR T cells redefine targetable CD70 expression in solid tumors [RNA-seq RCC]

Overcoming tumor antigen heterogeneity in solid tumors is a major challenge for cancer immunotherapies including chimeric antigen receptor (CAR) T cells. Unlike CD19 for B-cell malignancies, no target with pan-cellular expression in solid tumors and absence in normal vital cells has been identified. CD70 is a potential candidate, confined to immune cell subsets and aberrantly expressed in many solid tumors, albeit heterogeneously. We find that CD70 expression in heterogeneous tumors is not binary but ranges from high to very low, appearing negative. We show that CD70-heterogeneous tumors are efficiently eliminated by highly sensitive CD70 receptors where prototypic CAR T cells fail. We further identify an epigenetic signature that predicts targetable expression. These findings provide a potential strategy to treat a broad range of solid tumors.