To confirm that BLOC1S1 degradation in myeloma cell lines is IRE1 dependent, NCI-H929 and RPMI-8226 myeloma cell lines were treated with DTT in the presence or absence of the IRE1 RNase inhibitor 4μ8c, and BLOC1S1 expression was measured by SYBR green qPCR. This evidence concerns the gene ERN1 and plasma cell myeloma.