S100P and neoplasm: For SK-BR-3 cells, the SK-BR-3 S100P KD cells were more resistant to cisplatin compared with Scr cells (4 μM by 30.51%, 16 μM by 89.67%, 32 μM by 139.49%, 64 μM by 898.97%, all p < 0.001; 8 μM by 28.77%, p < 0.05), indicating that the tumor with high S100P expression is more sensitive to cisplatin chemotherapy (Figure 4D).