Key factors in the utilization of lactate as cellular fuel consist in overexpression/increased activity (achieved by post-translational modification) of LDHB, thatmainly oxidizes lactate into pyruvate [94], and MCT1, which is mainly associated with lactate cellular imports, whose overexpression by cancer cells in subtypes of BC was found to be associated with poor prognosis [95,96]. The gene discussed is LDHB; the disease is cancer.