STEAP2 and cancer: Identical analyses were performed for a variety of primary, immortalized, and cancer cell lines to search for potential CAR-T activation by cells that could exhibit sub-detectable levels of STEAP2 by FACS, but no appreciable cytokine release was detected in cocultures with cells other than the positive control C4-2, LNCaP, and Ad293 STEAP3-2 cells (Supplemental Figure 7).