Exceptional Response to Pembrolizumab in Metastatic ER+/HER2− Breast Cancer With Liver Metastases: A Case Report and Literature Review. - Celi, Claudia Villa; Peshin, Supriya; Dharia, Adit; Bashir, Faizan; Erica, Linden; Mayordomo, Jose I. (Case Reports in Oncological Medicine, 2025)