MYC and plasma cell myeloma: Notably, MYC signature scores determined for each HMCL did not correlate with GCN2iB response (R = −0.067, P = 0.829, Supplementary Fig. 8a) or ISR-GCN2 activity (R = 0.077, P = 0.802, Supplementary Fig. 8b), suggesting that ISR-GCN2 activation may not be uniquely related to MYC dysregulation in human myeloma.