CBFA2T3 - GLIS2 fusion

Transcriptome RNA sequencing is required for the detection of the CBFA2T3-GLIS2 fusion gene and for proper risk-based allocation of pediatric patients with AML in future clinical strategies. Haplo-HSCT with posttransplant cyclophosphamide-based conditioning may improve survival in children with AMKL harboring the fusion gene.

Vobra duo showed robust in vitro cytolytic activity against CD276 positive AML cells highlighting the need for ongoing preclinical evaluations of CD276 targeted therapies in AML. Given the established safety profile for vobra duo this provides a clear path for rapid translation to clinical use for high risk AML patients.

Here we describe CLEC2A, a novel AML-restricted cell surface target that is an ideal immunotherapeutic target. CLEC2A is highly expressed in KMT2A-r AML, entirely absent in normal hematopoietic cells, directly and causally linked to the KMT2A fusion, and can be used for target-directed cytotoxicity.

AML with RAM immunophenotype, a distinct form of pediatric AML with a poor prognosis, may pose a diagnostic challenge if presented as a soft tissue mass. A comprehensive immunophenotypic evaluation, including stem cell and myeloid markers, is critical for an accurate diagnosis of myeloid sarcoma with the RAM-immunophenotype. Our data demonstrated weak CD13 expression as an additional immunophenotypic finding.

We used a doxycycline-inducible knockout (Doxi-KO) system to deplete the fusion in three Cas9-transduced CBFA2T3-GLIS2 AML cell lines and one patient-derived-xenograft (PDX) model by targeting the fusion with two single guide RNAs (sgETO2 and sgGLIS2) and a non-targeting sgRNA (sgNT) as a negative control...We observed a block in the induction of myeloid and megakaryocytic differentiation induced by fusion KO when GATA1 was concurrently knocked out, consistent with the hypothesis that repressed expression of GATA1 in CBFA2T3-GLIS2 AML is critical for the differentiation arrest observed in the disease. In summary, we have validated a persistent dependency on CBFA2T3-GLIS2 in AML for disease maintenance in vitro and in vivo mediated in part by a block in differentiation through repressed GATA1, validating CBFA2T3-GLIS2 as a therapeutic target in this deadly disease.

We also identified potential markers for pediatric AMKL, namely, RACK1, ELOB, TRIR, NOP53, SELENOH, and CD81. Our work offered insight into the heterogeneity of pediatric acute megakaryoblastic leukemia and established the single-cell transcriptomic landscape of AMKL for the first time.

The dismal outcomes in pediatric non-DS-AMKL require more effective therapeutic interventions. The identification of CBFA2T3/GLIS2 fusions and/or RAM-immunophenotype is highly desirable as anti-CD56 may serve as a potential therapeutic intervention. The possible relationship between aberrant cCD3 and RAM immunophenotype in non-DS-AMKL is a novel finding.

Our results demonstrated a spectrum of cytogenetically cryptic NUP98 rearranged acute leukemia in children and young adults with poor prognosis, co-operation between NUP98-NSD1 fusion and FLT3-ITD in AML whereas novel NUP98-MLLT1 fusion and other gene mutations in ALAL-NOS. Importantly, caution is required in interpreting FISH result of the NUP98 probe and abnormal finding to be confirmed by NGS study. Remarkably, our case with apparently false NUP98 alteration exhibited the characteristic feature of a rare subtype of pediatric AML carrying a cytogenetically cryptic CBFA2T3-GLIS2 fusion: a peculiar immunophenotype and dismal prognosis.

The dismal outcomes in pediatric non-DS-AMKL require more effective therapeutic interventions. The identification of CBFA2T3/GLIS2 fusions and/or RAM-immunophenotype is highly desirable as anti-CD56 may serve as a potential therapeutic intervention. The possible relationship between aberrant cCD3 and RAM immunophenotype in non-DS-AMKL is a novel finding.

Mice received a backbone of either current standard of care chemotherapy (SOC; anthracycline plus cytarabine) or topotecan plus gemcitabine...Synergy experiments with ATM inhibitor AZD0156 demonstrated tremendous synergy with talazoparib in sensitive cell lines with almost no synergy in those that were resistant, suggesting that sensitive cell lines are unable to efficiently activate the HR pathway to repair double stranded breaks induced by PARP inhibition whereas resistant cells can overcome inhibition...Downregulation of PTEN is a candidate biomarker of response to PARP inhibitors in these patients. This data illuminates a promising therapeutic vulnerability in a patient population where new targeted treatments are vital to improve outcomes.

An early T-cell precursor lymphoblastic leukemia was raised in the differential diagnosis, but lack of CD2 and CD7 and bright CD56 expression makes this later diagnosis less likely. AML with “RAM” phenotype (bright CD56, dim to negative CD45 and CD38, HLA-DR negative) has been reported with a median age at diagnosis of 1.26 years and is associated with inv(16)(p13.3q24.3) CBFA2T3-GLIS2 fusion protein.

Her induction included cytarabine, daunorubicin, etoposide, gemtuzumab ozogamicin, and repeated intrathecal cytarabine until her CSF had cleared on three consecutive occasions...Her second course included epigenetic modification with decitabine and vorinostat, gemtuzumab ozogamicin, fludarabine, high-dose cytarabine, and idarubicin... AMKL with GLIS2 fusion and RAM phenotype is exceptionally difficult to treat with conventional therapy. Innovative solutions are desperately needed for this grave disease. Assessing Bcl-2 status and incorporating venetoclax and liposomal daunorubicin- cytarabine into initial therapeutic planning should be strongly considered in these patients.

Comprehensive genomic characterization provides critical information for diagnosis, risk stratification, and treatment decisions for patients with AMKL. Continued genetic and clinical characterization of these rare cancers will aid in improving patient management.

We also observed a weak-to-negative CD45 expression, being exceptional in AML. We here provide evidence that the combination of HLA-DR negativity and intense bright CD56 expression detects a rare and aggressive pediatric AML genetic lesion improving the diagnosis performance.