flow-cytometry-to-estimate-leukemia-stem-cells-primary-acute-myeloid

Flow Cytometry to Estimate Leukemia Stem Cells in Primary Acute Myeloid Leukemia and in Patient-derived-xenografts, at Diagnosis and Follow Up

Acute myeloid leukemia (AML) is a heterogeneous, and if not treated, fatal disease. It is the most common cause of leukemia-associated mortality in ...

CHU Lille

Univ. Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc - Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer

Paroxysmal nocturnal hemoglobinuria (PNH) and T cell large granular lymphocyte (LGL) leukemia--an unusual association: another cause of cytopenia in PNH.

NUP214-ABL1 fusion defines a rare subtype of B-cell precursor acute lymphoblastic leukemia that could benefit from tyrosine kinase inhibitors.

We report a case of myeloproliferative neoplasm (MPN) with an atypical t(9;22;15)(p24;q11;q21) translocation, leading to a BCR-JAK2 fusion, associated with a trisomy of chromosome 8 in clonal evolution at karyotype. Patient's evolution was marked by an aggressive clinical course with rapid progression to blast phase within the first year after diagnosis. Examination of matched chronic phase and blast crisis samples by SNP-array karyotyping identified secondary acquired cryptic genetic events at the time of lymphoblastic transformation, including biallelic IKZF1 alteration and EBF1 and CDKN2A/B codeletions. This case is the first report describing acquisition of secondary genetic events leading to acute lymphoblastic progression in a rare MPN with BCR-JAK2 fusion.

Acquisition of genomic events leading to lymphoblastic transformation in a rare case of myeloproliferative neoplasm with BCR-JAK2 fusion transcript.

CD81 is a cell surface protein which belongs to the tetraspanin family. While in multiple myeloma its expression on plasma cells is associated with worse prognosis, this has not yet been explored in acute myeloid leukemia (AML). We measured membrane expression of CD81 on AML cells at diagnosis, evaluated its association with AML characteristics and its influence on patient outcome after intensive chemotherapy in a cohort of 134 patients. CD81 was detected in 92/134 (69%) patients. Patients with AML expressing CD81 had elevated leukocyte count (P=0.02) and were more likely classified as intermediate or adverse-risk by cytogenetics (P<0.001). CD81 expression had a negative impact on survival (event-free survival, overall survival and relapse-free survival) in univariate (P<0.001) and in multivariate analyses (P=0.003, 0.002 and <0.001, respectively). CD81 has a negative impact on OS in patients with NPM1 mutation (P=0.01) and in patients ELN-favorable (P=0.002). In conclusion, this cell surface marker may be a new prognostic marker for diagnostic risk classification and a potential therapeutic target for drug development in AML.

Tetraspanin CD81 is an adverse prognostic marker in acute myeloid leukemia.

ETV6 is a target of recurrent aberrations in sporadic and familial acute lymphoblastic leukemia (ALL). Here, we report on a new pedigree with a germline ETV6 mutation in which the index patient and his father developed high hyperdiploid (HeH) ALL and polycythemia vera at age 13 and 51, respectively. The index patient achieved durable complete remission without transplantation but had persistent moderate thrombocytopenia without bleeding tendency. To determine the prevalence of ETV6 alterations in HeH-ALL, we screened 81 unrelated subjects with HeH-ALL by single nucleotide polymorphism array and high-throughput sequencing for the ETV6 gene. Overall, ETV6 microdeletions and mutations were identified in 9% of cases, all of which were somatic and considered as secondary events. Apart from the index patient, no germline ETV6 aberration was identified. Finally, we reviewed the literature for ETV6 germline aberrations and predispositions to ALL.

Thomas Boyer

Laboratoire d’hématologie

CHU Lille

Flow Cytometry to Estimate Leukemia Stem Cells in Primary Acute Myeloid Leukemia and in Patient-derived-xenografts, at Diagnosis and Follow Up