[1360] Prognostic Relevance of Immunophenotype and 6q Deletions in Waldenstrom's Macroglobulinemia

A Jiang, C Qi, Y Trieu, W Xu, D Reece, C Chen, H Chang. University Health Network, Toronto, Canada

Background: Waldenstrom's macroglobulinemia (WM) is a rare clinical syndrome characterized by a clonal lymphoplasmacytic bone marrow infiltrate and a serum IgM paraprotein. Surface markers such as CD5, CD10, and CD23 are not typically expressed in WM and their clinical relevance is unclear. We examined frequency and prognostic significance of those antigen expressions in the context with the most common genetic aberration ie, 6q deletions in a large cohort of WM patients.
Design: A total of 102 cases diagnosed with WM were entered into the study.The patient's immunophenotype assessed by multiparameter flow cytometry were reviewed and their lymphoplasmacytic cells were evaluated for chromosome 6q deletions by interphase fluorescence in situ hybridization (FISH).Clinical and laboratory data were reviewed.
Results: There were 63 males and 39 females with median age of 63 yrs. CD5, CD10, D23 were expressed in 15%, 12%, and 30%, respectively. FISH detected hemizygous 6q deletions in 32 (37%) of the 86 WM cases.CD23 expression was strongly associated with 6q deletions (p=0.002); patients with 6q deletions had higher C-reactive protein levels than non-deleted patients (p= 0.016).There was no correlation between CD5, CD10 or CD23 expression and other biological factors such as age, gender, hemoglobin, platelet count, viscosity, beta-2 microglobulin, albumin, IgM level and degree of bone marrow lymphoplasmacytic infiltration.The median follow-up was 57.5 months with median overall survival of 164 months and a 10-year survival rate of 63%.There was no significant difference in overall survivals (OS) among patients with or without any of the surface marker expressions. However, the time from diagnosis to the requirement of initial treatment (TTT) was significantly longer in patients with CD10 expression than those without CD10 (median 40.7 months vs. 3.0 months, p=0.031).There was no significant difference in TTT between patients with or without 6q deletions (median 2.2 months vs. 2.6 months, p=0.192), or OS in patients with and without del (6q) (163 months vs. not reached, p= 0.74).
Conclusions: Our study indicates that CD5, CD10 and CD23 can be variably expressed in WM, and CD23 expression may predict 6q deletions. CD10 expression may be considered as a favorable factor for a longer TTT. 6q deletions are frequently detected in WM but do not appear to influence the clinical outcome. Further studies on clinical trials with uniform treatment protocols and longer follow-up are required to further evaluate the role of immunophenotype and 6q deletions in WM.
Category: Hematopathology

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 210, Tuesday Morning


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