CD276 and cancer: The expression of STEAP2 as well as pan-cancer targets ERBB2 (HER2) and the tumor immune checkpoint cell-surface protein CD276 (B7H3; Fig. 6D–F; Supplementary Fig. S16C–S16E) seemed restricted to the LumA and LumB samples, in contrast to KLK2, STEAP1, FOLH1, and epithelial cell-surface protein TACSTD2 (TROP2; Fig. 6G; Supplementary Fig. S16F), which were also expressed in the LP samples.