Oncogenic MCT-1 (also known as MCTS1) activation in breast cancer was investigated using the Kaplan-Meier Plotter database [24], and we observed that high MCT-1 expression in patients was associated with lower overall survival (OS) in overall breast cancer (p = 0.0053) as well as in TP53 wild type (p = 0.024) (Additional file 1: Figure S1A), lymph node metastasis-free (p = 0.001), HER2-negative (p = 0.0067), luminal-A (p = 0.026) and luminal-B (p = 0.043) breast cancers than that of patients with low-level MCT-1. The gene discussed is MCTS1; the disease is breast cancer.