Multiple Myeloma "Stem Cell” Identified

Cancer researchers have identified the type of cell responsible for multiple myeloma, a type of cancer that originates in the bone marrow and causes the destruction of bone tissue.

Investigators at Johns Hopkins University (Baltimore, MD, USA) examined the protein markers present on the surface of myeloma cells growing in tissue culture and on the surface of myeloma cells taken from patients with the disease. They reported in the November 20, 2003, online edition of Blood that multiple myeloma cell lines and clinical specimens were characterized by malignant plasma cells that expressed the cell surface antigen syndecan-1 (CD138). Human multiple myeloma cell lines contained small (< 5%) subpopulations that lacked CD138 expression and had greater clonogenic potential in vitro than corresponding CD138+ plasma cells.

The authors concluded that B cells lacking CD 138 act as "stem cells” for multiple myeloma. These cells have the ability to replicate and subsequently differentiate into malignant CD138-expressing plasma cells.

"Because these two cells are biologically different, we may need two therapies, one to kill the plasma cells, or the visible part of the weed, and one to kill the root--the stem cells,” explained first author Dr. William Matsui, assistant professor of oncology at Johns Hopkins University. "Treatments that are directed at myeloma plasma cells are likely to produce visible results, but they will be temporary improvements unless we also target the myeloma stem cell.”




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