To explore the role of S100P in chemotherapeutic drug sensitivity in breast cancer, T47D (with Luminal HER2− subtype) and SK-BR-3 (with HER2+ subtype) cells were treated with different concentrations of paclitaxel and cisplatin, and cell viability was assessed by AlamarBlue assay. This evidence concerns the gene ERBB2 and breast carcinoma.