MCT1 and MCT4 play the most dominant role in the transport of monocarboxylates, and they have been found to be significantly upregulated and associated with poor prognosis in multiple malignant tumors including peritoneal carcinomatosis, prostate cancer, lymphoma, and oral cavity cancer (Pértega-Gomes et al., 2011; Simões-Sousa et al., 2016; Kim et al., 2018; Afonso et al., 2019). The gene discussed is SLC16A1; the disease is prostate cancer.