LAG3 and plasma cell myeloma: ERK1/2-dependent pathways up-regulate ICP ligands, such as lymphocyte-activation gene 3 (LAG-3) in melanoma [152], and PD-1L in malignant pleural mesothelioma [153], non small cell lung cancer [154], breast cancer [155], prostate cancer [32], bladder cancer, and multiple myeloma [156].