We previously reported a role for two members of the 19S regulatory complex, 26S proteasome non-ATPase subunits 1 (PSMD1) and 3 (PSMD3), in disease progression and drug resistance of chronic myeloid leukemia (CML) and several types of solid tumors [11,21]. The gene discussed is PSMD1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.