B2M and plasma cell myeloma: Studies performed with human primary cell lines have described CRISPR/Cas9 mediated elimination of β2m expression in hematopoietic stem cells [41] and very recently knock out of MHC II expression in primary human endothelial cells and murine multiple myeloma cells [42] by CRISPR/Cas9 targeting the CIIA locus was reported [43].