Moreover, the recent success of antibody–drug conjugates (ADC) in many late‐stage solid tumors have also ushered the needs of patient stratification biomarkers228 A few good examples include the success application of T‐DXd (a HER2–ADC) that is being approved for metastatic HER2+ breast cancer and sacituzumab govitecan (SG), a trophoblast cell‐surface antigen 2 (TROP2)‐targeting ADC.228. The gene discussed is TACSTD2; the disease is breast cancer.