The lactate-to-pyruvate ratio (Lac/Pyr) correlates strongly with HIF1α expression, linking metabolic activity to hypoxia and tumor volume, while also showing associations with lactate dehydrogenase A (LDHA) and monocarboxylate transporter 1 (SLC16A1/MCT1) expressions [146]. The gene discussed is SLC16A1; the disease is neoplasm.