[1542] Plasma Cell Myeloma: Correlation of Immunophenotype and Genetic Profile in 174 Patients

Reza Setoodeh, Lynn Moscinski, Saqib Razzaque, Mojdeh Naghashpour. University of South Florida, Tampa, FL; Moffitt Cancer Center, Tampa, FL

Background: Plasma cell myeloma (PCM) is a bone marrow-based neoplasm of plasma cells associated with a monoclonal protein in serum and/or urine, accounting for 10-15% of hematopoietic neoplasms. The wide spectrum of clinical features and variable survival rate ranging from less than 6 months to more than 10 years demonstrates the heterogenous nature of PCM. Among well recognized poor prognostic factors are genetic abnormalities detected by cytogenetic and/or FISH analyses, which include del 13q, t(4;14), t(4;16), t(4;20), and del 17p/T53. Although flow cytometry (FC) is useful in diagnosis of PCM, characterizing the immunophenotypic profile of neoplastic plasma cells, little data is available regarding the association of immunophenotypic and genetic profile of malignant cells. This study examines potential association of aberrant antigen expression, CD56 (a neural cell adhesion molecule) and/or CD117 (a tyrosine kinase receptor) and genetic abnormalities in PCM.
Design: Cases of PCM reviewed between 03/2009 and 03/2011 were retrieved from Moffitt Cancer Center electronic database. Genetic abnormalities of malignant cells and aberrant expression of CD56 and CD117 detected respectively by FISH analysis and flow cytometry were reviewed and analyzed.
Results: Among our 174 cases of PCM, flow cytometry revealed aberrant expression of CD56 in 120 cases (120/174; 70%) and CD117 in 79 patients (79/174; 45%), with co-expression in 61 cases (61/174; 35%). Thirty six cases lacked expression of CD56 and CD117 (36/174; 21%). FISH analysis, using a myeloma-specific panel of probes was performed which identified genetic aberrancies in 124 cases (124/174; 71%), although fifty cases (50/174) showed no abnormalities by conventional karyotyping. 59% of CD117 expressing and 77% of CD117 negative myelomas revealed at least one of poor prognostic molecular changes: del 13q, t(4;14), t(4;16), t(4;20), and del 17p/T53.
Conclusions: The majority (79%) of PCM cases in our study, showed aberrant expression of CD56 and/or CD117. By flow cytometry 69% of cases were CD56 (+)ve, 45% showed positivity for CD117, and 35% revealed co-expression of these antigens. Lack of CD117 expression is found to be associated with a higher rate of poor prognostic molecular abnormalities detected by FISH analysis, 77% compared 59% in CD117 expressing cases. More studies are required to further elucidate the clinical significance of these findings.
Category: Hematopathology

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 227, Wednesday Afternoon


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