To address to what extent NFV or LPV likewise sensitizes myeloma cells to next-generation PIs, we established the IC50 for the approved proteasome inhibiting drugs or drug candidates: BTZ, ixazomib, delanzomib (peptide boronate-based), CFZ, oprozomib, the immunoproteasome-selective PR957 (epoxyketone) and the β-lactone marizomib, in the presence/absence of NFV or LPV by viability assays. The gene discussed is CASC3; the disease is plasma cell myeloma.