In a phase I clinical trial for patients with metastatic HR+/HER2- and TN BC (SGNLVA-001 trial: NCT01969643), out of 614 screened samples for LIV-1 status, 90% were positive, with moderate-to-high expression being detected in 82% of ER+/HER2- samples, 73% of HER2+, and 68% of TN. Here, ESR1 is linked to breast cancer.