89. TCF3::ZNF384 in a Peruvian girl with mixed-phenotype acute leukemia and poor treatment outcome

Aly Abdelkareem

Richard S. Rodriguez

Medical Geneticist at Instituto Nacional de Salud del Nio San Borja of Peru and graduate of the Master’s program in Epidemiological Research at Cayetano Heredia University. Main research interests in analysis and clinical interpretation of genomic variations in Peruvian population, genomic cancer medicine and genetic epidemiology. Currently, I collaborate in the clinical interpretation of somatic and germline genetic variants in the pediatric population with leukemias in Peru. Main research interests are to contribute to the analysis and clinical interpretation of genomic variations, cancer genomic medicine and genetic epidemiology in Peruvian population.


Richard S. Rodriguez, Jeny Bazalar-Montoya, Ricardo Abanto-Hinostroza, Mirian Conde-Fanola, Mabel Aucca-Vitorino, Victoria Godoy-Vila, Gioconda Manassero-Morales

Instituto Nacional de Salud del Niño San Borja; School of P, Lima, Peru

Introduction: ZNF384 rearrangements are common in B cell/myeloid mixed phenotype acute leukemias (B/M MPAL) with poor steroid response and a high frequency of relapse. A distinct subtype of MPAL is defined according to WHO. In order to contribute to the clinical genetic landscape of pediatric MPAL.

Methods: Genetic characterization by NGS from DNA and RNA of leukemic cells at diagnosis. Immunophenotyping and minimal residual disease (MRD) by flow cytometry.

Results: A 4-year-old girl is admitted to our hospital for suspected clinical leukemia with a white blood cell count of 203.6 x 103/µL, a hemoglobin level of 3.9 g/dL, a platelet count of 10.2 x 103/µL and 78% blasts in peripheral blood. Immunophenotype was B/M MPAL (positive: CD19, CD79a, CD22, MPO, CD64, CD13 and CD14; negative: CD10). TCF3::ZNF384 was detected by NGS (UMI: 1832 unit molecular count), exon 5 of TCF3 was fused to exon 3 of ZNF384 not previously reported. An ALL-like induction regimen was initially planned but due to steroid resistance she was switched to an AML-like regimen. MRD in bone marrow was 5.0%. Then, she received an HAM reinduction regimen. MRD 1.7% was evidenced in bone marrow. Recently, FLAG IDA regimen was started looking for the first complete remission followed by an allogeneic stem cell transplant.

Conclusions: Although NGS identified the first Peruvian case of B/M MPAL with TCF3::ZNF384, qPCR and FISH were not available at our institution. Future collaborative studies will allow us to identify more cases and estimate clinical significance of this fusion gene.