In:
Pathobiology, S. Karger AG, Vol. 86, No. 2-3 ( 2019), p. 162-166
Abstract:
〈 b 〉 〈 i 〉 Background: 〈 /i 〉 〈 /b 〉 RUNX1 is a crucial transcription factor for hematological stem cells and well-known for its association with acute lymphoblastic leukemia (ALL) and acute myelogenous leukemia (AML). Besides the translocation t(8; 21) that leads to the 〈 i 〉 RUNX1 〈 /i 〉 - 〈 i 〉 RUNX1T1 〈 /i 〉 fusion, somatic mutations of 〈 i 〉 RUNX1 〈 /i 〉 have been discovered. 〈 b 〉 〈 i 〉 Methods: 〈 /i 〉 〈 /b 〉 Four bone marrow trephine biopsies of patients with CD79a-positive and/or PAX5-positive acute leukemias were investigated by immunohistochemistry (IHC), karyotyping, and next-generation sequencing-based genetic analysis. Data were then compared to a historical collective of AML ( 〈 i 〉 n 〈 /i 〉 = 42) and 42 cases of AML newly diagnosed at our institution between June 2017 and May 2018. 〈 b 〉 〈 i 〉 Results: 〈 /i 〉 〈 /b 〉 We report on 4 cases of acute leukemia with an equivocal immunophenotype showing expression of CD79a and/or PAX5, which led to a preliminary histopathologic classification as probable ALL/unclassifiable acute leukemia. All cases were positive for CD34 and TdT but negative for several myeloid markers on IHC. Mutational analysis revealed point mutations and indels of 〈 i 〉 RUNX1 〈 /i 〉 and further mutations typical for AML such as 〈 i 〉 TET2 〈 /i 〉 , 〈 i 〉 DNMT3A 〈 /i 〉 , and 〈 i 〉 SRSF2 〈 /i 〉 , and 2 cases had tetrasomy 13 characteristic of 〈 i 〉 RUNX1 〈 /i 〉 mutant AML. 〈 b 〉 〈 i 〉 Conclusion: 〈 /i 〉 〈 /b 〉 Aberrant CD79a and/or PAX5 expression can be found in AML cases with 〈 i 〉 RUNX1 〈 /i 〉 mutations even without the translocation t(8; 21). Our series shows the expression of CD79a and PAX5 to be a potential pitfall in the classification of 〈 i 〉 RUNX1 〈 /i 〉 mutant acute leukemia.
Type of Medium:
Online Resource
ISSN:
1015-2008
,
1423-0291
Language:
English
Publisher:
S. Karger AG
Publication Date:
2019
detail.hit.zdb_id:
1483541-1
SSG:
12
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