DEK-NUP214-Fusion Identified by RNA-Sequencing of an Acute Myeloid Leukemia with t(9;12)(q34;q15)

The adult HNRNPH1::ERG positive acute myeloid leukemia with clear lower remission and worse prognosis: A case report and review of the literature

RATIONALE

Acute myeloid leukemia (AML) derived from t(5;21)(q35;q22) translocation, post-transcriptional translation, forming the HNRNPH1::ERG fusion gene is a rare group of recurrent chromosomal abnormality myeloid malignancies. Only 1 adult case of AML has been reported so far. Here we identified a disparate adult case of HNRNPH1::ERG positive AML with clear breakpoint locations by utilizing The RNA sequencing(RNA-seq) and we addressed the clinical, treatment, pathological and molecular mechanism, along with a review of the literature.

PATIENTS CONCERNS

A 54-year-old man visited our department with fever and fatigue for 10 days.

DIAGNOSES

Diagnosed with acute myeloid leukemia (AML) through morphology, immunology, Cytogenetics, and Molecular biology (MICM) typing, with a confirmed HNRNPH1-ERG fusion gene.

INTERVENTIONS

Multiple induction chemotherapy combined with targeted therapy was performed.

OUTCOMES

He died in February 2024.

LESSONS

In our review, Only 1 adult case of AML has been reported so far. To summarize the 5 cases in the studies, the HNRNPH1::ERG positive AML cases had a significantly higher blast cell counts and more frequently companied with rare gene mutations, which characterized poorer prognosis and lower remission in adult HNRNPH1::ERG positive AML.

Therapy-induced Deletion in 11q23 Leading to Fusion of KMT2A With ARHGEF12 and Development of B Lineage Acute Lymphoplastic Leukemia in a Child Treated for Acute Myeloid Leukemia Caused by t(9;11)(p21;q23)/KMT2A-MLLT3

BACKGROUND/AIM

Fusion of histone-lysine N-methyltransferase 2A gene (KMT2A) with the Rho guanine nucleotide exchange factor 12 gene (ARHGEF12), both located in 11q23, was reported in some leukemic patients. We report a KMT2A-ARHGEF12 fusion occurring during treatment of a pediatric acute myeloid leukemia (AML) with topoisomerase II inhibitors leading to a secondary acute lymphoblastic leukemia (ALL).

MATERIALS AND METHODS

Multiple genetic analyses were performed on bone marrow cells of a girl initially diagnosed with AML.

RESULTS

At the time of diagnosis with AML, the t(9;11)(p21;q23)/KMT2A-MLLT3 genetic abnormality was found. After chemotherapy resulting in AML clinical remission, a 2 Mb deletion in 11q23 was found generating a KMT2A-ARHGEF12 fusion gene. When the patient later developed B lineage ALL, a t(14;19)(q32;q13), loss of one chromosome 9, and KMT2A-ARHGEF12 were detected.

CONCLUSION

The patient sequentially developed AML and ALL with three leukemia-specific genomic abnormalities in her bone marrow cells, two of which were KMT2A-rearrangements.

Novel GTF2I-PDGFRB and IKZF1-TYW1 fusions in pediatric leukemia with normal karyotype

Background

Many cases of acute lymphoblastic leukemia (ALL) carry visible acquired chromosomal changes of pathogenetic, diagnostic, and prognostic importance. Nevertheless, from one-fourth to half of newly diagnosed ALL patients have no visible chromosomal changes detectable by G-banding analysis at diagnosis. The introduction of powerful molecular methodologies has shown that many karyotypically normal ALLs carry clinically important submicroscopic aberrations.

Case presentation

We used fluorescence in situ hybridization (FISH), array comparative genomic hybridization (aCGH), RNA sequencing, reverse transcription (RT) and genomic polymerase chain reaction (PCR), as well as Sanger sequencing to investigate a case of pediatric ALL with a normal karyotype. FISH with a commercial PDGFRB breakapart probe showed loss of the distal part of the probe suggesting a breakpoint within the PDGFRB locus. aCGH revealed submicroscopic deletions in chromosome bands 5q32q35.3 (about 30 Mb long, starting within PDGFRB and finishing in the CANX locus), 7q34 (within TCRB), 9p13 (PAX5), 10q26.13 (DMBT1), 14q11.2 (TRAC), and 14q32.33 (within the IGH locus). RNA sequencing detected an in-frame GTF2I–PDGFRB and an out-of-frame IKZF1–TYW1 fusion transcript. Both fusion transcripts were verified by RT-PCR together with Sanger sequencing and interphase FISH. The GTF2I–PDGFRB fusion was also verified by genomic PCR and FISH. The corresponding GTF2I–PDGFRB fusion protein would consist of almost the entire GTF2I and that part of PDGFRB which harbors the catalytic domain of the tyrosine kinase. It would therefore seem to lead to abnormal tyrosine kinase activity in a manner similar to what has been seen for other PDGFRB fusion proteins.

Conclusions

The examined pediatric leukemia is a Ph-like ALL which carries novel GTF2I–PDGFRB and IKZF1–TYW1 fusion genes together with additional submicroscopic deletions. Because hematologic neoplasms with PDGFRB-fusion genes can be treated with tyrosine kinase inhibitors, the detection of such novel fusions may be clinically important. Since the GTF2I–PDGFRB could be detected only after molecular studies of the leukemic cells, further investigations of ALL-cases, perhaps especially but not exclusively with a normal karyotype, are needed in order to determine the frequency of GTF2I–PDGFRB in leukemia, and also to find out which clinical impact the fusion may have.

RUNX1-PDCD6 fusion resulting from a novel t(5;21)(p15;q22) chromosome translocation in myelodysplastic syndrome secondary to chronic lymphocytic leukemia

Leukemic cells often carry chromosome aberrations which generate chimeric genes of pathogenetic, diagnostic, and prognostic importance. New rearrangements giving rise to novel fusion genes define hitherto unrecognized genetic leukemia subgroups. G-banding, fluorescence in situ hybridization (FISH), and molecular genetic analyses were done on bone marrow cells from a patient with chronic lymphocytic leukemia (CLL) and secondary myelodysplasia. The G-banding analysis revealed the karyotype 46,XX,del(21)(q22)[9]/46,XX[2]. FISH on metaphase spreads with a RUNX1 break apart probe demonstrated that part of RUNX1 (from 21q22) had moved to chromosome band 5p15. RNA sequencing showed in-frame fusion of RUNX1 with PDCD6 (from 5p15), something that was verified by RT-PCR together with Sanger sequencing. Further FISH analyses with PDCD6 and RUNX1 home-made break apart/double fusion probes showed a red signal (PDCD6) on chromosome 5, a green signal on chromosome 21 (RUNX1), and two yellow fusion signals, one on der(5) and the other on der(21). Reassessment of the G-banding preparations in light of the FISH and RNA-sequencing data thus yielded the karyotype 46,XX,t(5;21)(p15;q22)[9]/46,XX[2]. The t(5;21)(p15;q22)/RUNX1-PDCD6 was detected only by performing molecular studies of the leukemic cells, but should be sought after also in other leukemic/myelodysplastic cases with del(21q).