Genomics and proteomics in multiple myeloma and Waldenström macroglobulinemia

Waldenström macroglobulinemia: clinical and immunological aspects, natural history, cell of origin, and emerging mouse models

Waldenström macroglobulinemia (WM) is a rare and currently incurable neoplasm of IgM-expressing B-lymphocytes that is characterized by the occurrence of a monoclonal IgM (mIgM) paraprotein in blood serum and the infiltration of the hematopoietic bone marrow with malignant lymphoplasmacytic cells. The symptoms of patients with WM can be attributed to the extent and tissue sites of tumor cell infiltration and the magnitude and immunological specificity of the paraprotein. WM presents fascinating clues on neoplastic B-cell development, including the recent discovery of a specific gain-of-function mutation in the MYD88 adapter protein. This not only provides an intriguing link to new findings that natural effector IgM⁺IgD⁺ memory B-cells are dependent on MYD88 signaling, but also supports the hypothesis that WM derives from primitive, innate-like B-cells, such as marginal zone and B1 B-cells. Following a brief review of the clinical aspects and natural history of WM, this review discusses the thorny issue of WM's cell of origin in greater depth. Also included are emerging, genetically engineered mouse models of human WM that may enhance our understanding of the biologic and genetic underpinnings of the disease and facilitate the design and testing of new approaches to treat and prevent WM more effectively.

The use of cell lines for the study of Waldenström's macroglobulinemia

In this issue of Leukemia Research, Drexler and MacLeod raise questions about the origins of cell lines used in the study of Waldenström's macroglobulinemia and suggest caution in the use of these cell lines as models of this disease [Drexler HG, Macleod RAF. Malignant hematopoietic cell lines: in vitro models for the studies of Waldenström's macroglobulinemia. Leuk Res 2008].

[Chromosomal abnormalities and Waldenström macroglobulinemia]

Waldenström macroglobulinemia (WM) is now defined as an uncommon lymphoplasmocytic proliferation associated with an immunoglobulin M peak. The associated chromosomal abnormalities are not specific to the disease, and changes in the diagnostic criteria and techniques used as well as low-level abnormal cell proliferation made their analysis difficult. A literature review however, shows that if specific abnormalities were not recognized until now, it is the frequency of some chromosomal abnormalities (for instance partial deletion of the long arm of chromosome 6 and trisomy 4) that distinguishes WM from other chronic malignant B-cell proliferations. The data collected in the present review show directions for future research which will benefit from use of more recent techniques such as fluorescent in situ hybridization, comparative genomic hybridization and expression microarrays.