[1333] Factor XIII Subunit A Immunohistochemical Expression Is Associated with an Inferior Outcome in Acute Promyelocytic Leukemia

Aaron N Berg, Christine Roth, Marian A Rollins-Raval. University of Pittsburgh Medical Center, Pittsburgh, PA

Background: Coagulation Factor XIII Subunit A (FXIIIa) intracellular expression has been described in platelets, megakaryocytes, and monocytic cells, as well as leukemic blasts. Flow cytometric-based studies have suggested prognostic implications, especially within the acute promyelocytic leukemia (APL) subgroup of acute myeloid leukemia (AML); however, the immunohistochemical (IHC) correlate is unknown. The aim of this study was to define clinicopathologic features of FXIIIa IHC+ AML and compare APL to other AML subtypes.
Design: 87 bone marrow biopsies or clot/particle preparations from our institution were evaluated with with FXIIIa IHC (N1N3 clone, GeneTex). The study cohort consisted of: 36 consecutive pre-therapy APL, 42 selected pre-therapy non-APL AML {5 therapy-related AML, 19 AML with recurrent cytogenetic abnormalities [9 with inv(16), 6 with t(8;21), 2 with t(6;9), 1 each with inv(3) and t(9;11)], 8 AML with myelodysplasia related changes and 10 AML, not otherwise specified}, and 9 negative staging bone marrow evaluations. FXIIIa IHC expression was correlated with clinical & pathologic features and Kaplan-Meier overall survival (OS).
Results: Leukemic blast FXIIIa cytoplasmic positivity was noted in 56% (20/36) APL and 74% (31/42) non-APL AML (P=0.091). AML FXIIIa IHC expression was not significantly associated with age at diagnosis, sex, percentage of bone marrow blasts, percentage of peripheral blood blasts, platelet count, morphologic dysplasia, history of myelodysplastic syndrome, or monocytic differentiation. FXIIIa IHC expression was associated with a worse OS within the APL cohort (p=0.035).

No OS differences were noted in comparing FXIIIa IHC expression in all AML (P=0.144), or FXIIIa IHC expression within the favorable, intermediate or adverse cytogenetic groups (P=0.20, 0.23 and 0.87, respectively).
Conclusions: FXIIIa IHC expression is seen among a broad spectrum of AML subtypes and is not characterized by specific pathologic features. However, within the APL subgroup, FXIIIa IHC expression is associated with an inferior outcome, and may be useful for additional prognostic risk stratification.
Category: Hematopathology

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 201, Monday Morning

 

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