USP7 and plasma cell myeloma: In terms of clinical application, since the approval of the first-in-class proteasome inhibitor bortezomib (Velcade®) by the Food and Drug Administration (FDA) for the treatment of relapsed multiple myeloma in 2003 [50], an increasing number of research groups as well as industrial companies have developed more flexible and efficient chemical synthesis protocols to identify better compounds targeting USP7 with high affinity, specificity, cell permeability, and stability.