In parallel assays, we observed superior tumor regression in a FRαpos SKOV3 ovarian cancer xenograft model where mice were treated with the same FRα CAR T cells (Additional file 3: Figure S3), reflecting a disparity in the killing of TNBC MDA-231 tumors versus FRαpos SKOV3 ovarian tumors in vivo. Here, FOLR1 is linked to ovarian cancer.