In both human myeloma cell lines (HMCLs), RPMI-8226 and MM1S, inhibition of MYC protein expression by MYCi975 was associated with decreased MCT1 expression and a compensatory increase of MCT4 further supporting the association of MCT1 in the pathogenesis of MM (Supplementary Fig. 1G). Here, MYC is linked to plasma cell myeloma.