This study aimed to investigate the mechanisms and predictive models underlying chemotherapy resistance in HR+/HER2- breast cancer.<h4>Methods</h4>Patient-derived primary cancer cell lines (PCCLs) were successfully established from four patients with HR+/HER2- breast cancer (Luminal B, HER2 non-amplified) using primary cell culture techniques. This evidence concerns the gene ERBB2 and breast carcinoma.