Flow cytometry as a tool for the study of the tumor microenvironment in multiple myeloma
Basic Information
Description
The bone marrow (BM) microenvironment in multiple myeloma has been recognized as an important player in the development of the tumor, that allows the homing of clonal plasma cells (PC) to the BM; the spread of tumor by the bloodstream to a second site; the generation of paracrine factors that are involved in the survival, differentiation and proliferation of tumor cells; angiogenesis; osteoclastogenesis; inhibition of osteogenesis; humoral and cellular immunodeficiency. The bone marrow mesenchymal stromal cells (MSC) are one of the most important cells in the BM microenvironment harboring immunomodulatory functions. Also, the enhanced angiogenesis accompanies tumor progression. In advantage stages, the MM cells become independent from the tumor microenvironment downregulating receptors that maintain these cells attached in the BM and reach the bloodstream to colonize different sites, indicating a more aggressive disease. The emergence of new-generation drugs has dramatically improved patient outcomes in MM, with an increment of deeper responses to therapy and extending the survival and quality of life in MM patients. Even with these new strategies, patients might achieve and maintain a serological complete response (CR), with variable clinical outcomes and different evolutions of intramedullary and extramedullary disease. A way of assessing tumor heterogeneity in a minimally invasive method in MM patients may be the use of liquid biopsies, emerging as a minimally invasive technique for identifying and analyzing circulating tumor PC and cell products produced by tumors and released into the circulation, allowing for the comprehensive detection of disease burden, molecular alterations, monitoring treatment response and disease progression. The development of new markers and approaches to assess more accurately and quickly the tumor burden would result in better outcomes.
