TNFRSF17 and cancer: Most innovations to date, however, have focused on improving the odds of successful target binding on cancer cells through one of four approaches (1): alternative BCMA targeting domains (2), modulation of CAR or target antigen density (3), dual targeting of BCMA alongside other antigens, and (4) “armored” CARs to help CAR-T cells penetrate the tumor microenvironment.