IL6 and cancer: Several humanized monoclonal antibodies against soluble and membrane bound IL-6R (tocilizumab, REGN88) or against IL-6 (siltuximab and sirukumab) are currently in clinical trials at various development stages for several types of cancer including MM, metastatic renal cell carcinoma, B-cell lymphoproliferative diseases (Heo et al., 2016).