The tumor microenvironment as a determinant of cancer cell survival: a possible mechanism for de novo drug resistance

The influence of the microenvironment in the pathogenesis and progression o f human cancer has traditionally been considered in the context of solid tu mors. More recently, evidence has been accumulating to support the role of the bone marrow microenvironment in hematologic malignancies as well, parti cularly in multiple myeloma. This review focuses on myeloma as a model to d emonstrate that the bone marrow microenvironment provides a sanctuary again st programmed cell death and promotes tumor cell survival and progression, Additionally, the protective effects of the bone marrow milieu may confer a protection from cytotoxic drugs, allowing the emergence of drug-resistant tumors. These advances may assist in the design of novel therapeutic approa ches to enhance the efficacy of standard chemotherapeutic drugs. Curr Opin Oncol 2000, 12:557-563 (C) 2000 Lippincott Williams & Wilkins, Inc.