ABSTRACT
BACKGROUND: Ewing sarcoma breakpoint region 1 gene (EWSR1) rearrangements are largely associated with the Ewing sarcoma family of tumors. OBSERVATIONS: We report the first case of infantile, mixed phenotype acute leukemia, B/myeloid (bilineal and biphenotypic [B-lymphoid and B-lymphoid/myeloid]), with a t(2;22)(q35;q12). The EWSR1-fifth Ewing variant gene fusion and nonsense mutation in STAG2 were detected by next-generation sequencing and markedly high expression of fifth Ewing sarcoma variant mRNA detected by quantitative reverse transcription polymerase chain reaction. The patient was treated with a combined myeloid/lymphoid leukemia regimen followed by allogeneic stem cell transplant and was in complete remission at 3.8-year follow-up. CONCLUSIONS: Our case study underscores the importance of a comprehensive evaluation of acute leukemia and provides insights into the phenotype of EWSR1 rearranged neoplasms in the context of partner genes and cell type.
Subject(s)
DNA-Binding Proteins/genetics , Leukemia, Biphenotypic, Acute/genetics , Leukemia, Myeloid, Acute/genetics , Oncogene Proteins, Fusion/genetics , RNA-Binding Protein EWS/genetics , Transcription Factors/genetics , Cell Cycle Proteins/genetics , Codon, Nonsense , Female , Humans , Infant , Translocation, GeneticABSTRACT
BACKGROUND: High-grade B-cell lymphomas (HGBCL) with MYC and BCL2 or/and BCL6 rearrangements (R), so-called double/triple-hit lymphomas (DH/THL), are uncommon, clinically aggressive lymphomas that require a prompt diagnosis. We aim to identify flow cytometric immunophenotypic (IP) features of DH/THL that may aid in triaging these cases followed by a timely confirmatory cytogenetic study. METHODS: We compared the IP features of 43 cases of DH/THL to those of 55 cases of single-hit lymphoma (SHL) and 59 cases of diffuse large B-cell lymphoma (DLBCL) without MYC-R (MYCneg DLBCL). We analyzed the expression patterns of CD10, CD19, CD20, CD38, and surface immunoglobulin light chain in lymphoma cells. RESULTS: Bright CD38 expression (CD38bright ) analyzed either qualitatively or semi-quantitatively was more common in DH/THL (56%) than in MYCneg DLBCL (17%) but less common compared to SHL (82%), indicating that CD38bright can serve as a biomarker for DH/THL. Additionally, CD38bright may be a better indicator for predicting DH/THL-BCL2 than DHL-BCL6, and very bright CD38 expression was exclusive to MYC rearranged lymphomas. The expression patterns of other markers were similar among these lymphoma groups. CONCLUSIONS: CD38bright is a biomarker associated with DH/THL with a moderate sensitivity (~50%) and high specificity (~90%). While this marker cannot be used as a screening tool, awareness of this correlation may aid in expediting the diagnosis and prioritizing FISH testing in resource limited settings or situations when samples are limited. Future studies to combine immunohistochemical markers are needed to further enhance the predictive power of CD38bright in diagnosing DH/THL. © 2019 International Clinical Cytometry Society.