[1225] Clinicopathologic Analysis of the Impact of CD23 Expression in Plasma Cell Myeloma with t(11;14)(q13;q32).

J Noelle Buonaccorsi, Steven H Kroft, Alexandra Harrington, Peter VanTuinen, Horatiu Olteanu. Medical College of Wisconsin, Milwaukee

Background: The t(11;14)(11q13;14q32) occurs in 15-18% of plasma cell myelomas (PCMs), and is thought to have a neutral to slightly positive impact on prognosis. CD23, a low-affinity Fc receptor for IgE found on a subset of B-cells, is frequently expressed in non-Hodgkin lymphoma, and is used to differentiate chronic lymphocytic leukemia/small lymphocytic lymphoma from mantle cell lymphoma. A recent study has shown that 10% of PCMs express CD23, and that expression is specifically associated with abnormalities of chromosome 11, mainly t(11;14); however, only 40% of t(11;14)(+) PCMs express CD23. Since the clinical relevance of CD23 expression in PCMs with t(11;14) has not been fully characterized, we addressed this question in a large series of patients (pts) with t(11;14)(+) PCM.
Design: 42 bone marrow (BM) biopsies from pts with t(11;14)(+) PCM were evaluated for CD23 expression by immunohistochemistry (IHC). Expression of CD23 was correlated with presenting laboratory and clinical data, as well as event-free survival (EFS) after autologous stem cell transplant (SCT) and overall survival (OS).
Results: There were 42 pts (M:F=25:17) with a median age at diagnosis of 61 years (range 32-81) and a median f/u of 902 days (104-4998). By flow cytometry, the cases were frequently CD20(+) (46.4%) and CD56(-) (53.8%), and had a non-hyperdiploid karyotype (97.6%) with frequent 13q deletion (33.3%). 16/42 pts (46%) expressed CD23. Compared to negative cases, CD23(+) PCMs were more likely to present with platelet counts<150,000/uL (100% vs. 50%, p=0.006). There were no significant differences in immunophenotype (IP) and other presenting laboratory and clinical data (other blood counts, M-protein level, creatinine, beta-2 microglobulin, calcium, albumin, lactate dehydrogenase, % BM PCs, immunoglobulin isotype, age, sex, stage, other cytogenetic findings) between CD23(+) and CD23(-) cases. The median EFS in pts treated with autologous SCT (n=29) was similar regardless of CD23 status, while the median OS (all pts) was marginally longer in CD23(-) than in CD23(+) PCMs: not reached vs. 3365 days (p=0.08).
Conclusions: We have found that CD23 is expressed in 46.4% of PCMs with t(11;14), confirming the strong association between this IP and abnormalities of chromosome 11 noted in a previous study. Our study corroborates previously reported associations of t(11;14) with expression of CD20 and lack of CD56, a non-hyperdiploid karyotype, and frequent deletion 13q in PCM. Pts with t(11;14)(+)/CD23(+) PCM tend to present with lower platelet counts and may have a shorter OS than those with t(11;14)(+)/CD23(-) PCM.
Category: Hematopathology

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 242, Tuesday Morning

 

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