Preface During the past two decades, the paradigm for cancer treatment has evolved from relatively non-specific cytotoxic agents to selective, mechanism-based therapeutics. Cancer chemotherapies were initially identified through screens for compounds that killed rapidly dividing cells. These drugs remain a backbone of current treatment, but are limited by a narrow therapeutic index, significant toxicities, and frequently acquired resistance. More recently, an improved understanding of cancer pathogenesis has given rise to new treatment options, including targeted agents and cancer immunotherapy. Targeted approaches aim to inhibit molecular pathways that are critical to tumor growth and maintenance, whereas immunotherapy endeavors to stimulate a host response that effectuates long-lived tumor destruction. Targeted therapies and cytotoxic agents also modulate immune responses, which raises the possibility that these treatment strategies might be effectively combined with immunotherapy to improve clinical outcomes.

Monoclonal gammopathy of undetermined significance (MGUS) is