PDCD1 and plasma cell myeloma: Moreover, pharmacological inhibition of MYC resulted in a downregulation of PD-L1 expression in malignant plasma cell clones upon early transgenic MYC activation, indicating that early myeloma subclones with alterations in the MYC oncogene may express PD-L1 thus preventing their elimination by PD-1+ CD8+ cytotoxic T cells (165).