Magic™ Anti-Nucleophosmin (Phospho T95) monoclonal antibody, clone FQODJS228

FLT3-ITD and FLT3-TKD mutations were observed in approximately 20 and 10% of acute myeloid leukemia (AML) cases, respectively. FLT3 inhibitors such as midostaurin, gilteritinib and quizartinib show excellent response rates in patients with FLT3-mutated AML, but its duration of response may not be sufficient yet. The majority of cases gain secondary resistance either by on-target and off-target abnormalities. On-target mutations (i.e., FLT3-TKD) such as D835Y keep the TK domain in its active form, abrogating pharmacodynamics of type II FLT3 inhibitors (e.g., midostaurin and quizartinib). Second generation type I inhibitors such as gilteritinib are consistently active against FLT3-TKD as well as FLT3-ITD. However, a "gatekeeper" mutation F691L shows universal resistance to all currently available FLT3 inhibitors. Off-target abnormalities are consisted with a variety of somatic mutations such asNRAS,AXLandPIM1that bypass or reinforce FLT3 signaling. Off-target mutations can occur just in the primary FLT3-mutated clone or be gained by the evolution of other clones. A small number of cases show primary resistance by an FL-dependent, FGF2-dependent, and stromal CYP3A4-mediated manner. To overcome these mechanisms, the development of novel agents such as covalently-coupling FLT3 inhibitor FF-10101 and the investigation of combination therapy with different class agents are now ongoing. Along with novel agents, gene sequencing may improve clinical approaches by detecting additional targetable mutations and determining individual patterns of clonal evolution.

IntroductionAML with inv(3)(q21.3q26.2) or t(3;3)(q21.3;q26.2) [inv(3)/t(3;3)] was very rare. Currently, most reports of AML-inv(3)/t(3;3) were from Western countries, and few reports were from Asian countries. Racial differences in patients with AML-inv(3)/t(3;3) are still unknown. MethodsBetween January 1996 and April 2018, a total of 37 AML cases with inv(3)/t(3;3) were studied retrospectively. They were collected from 2229 primary AML cases performed with conventional cytogenetic analysis (37/2229, 1.66%). ResultsHere, some differences were found by comparing our data with those from Western countries. In our series, AML with inv(3)(q21q26) had a lower incidence than that with t(3;3)(q21;q26) (11 vs 26 cases). Our patients seemed to be more younger (median, 43years) and have lower hemoglobin concentrations (median, 73g/L) and higher platelet count (median, 351x10(9)/L). A higher incidence of acute monoblastic and monocytic leukemia (45.9%) was observed in our patients. Immunophenotypic studies showed that CD38 (30.8%) was not so frequently expressed as that in the earlier reports. Mutations analysis showed a high frequency of NRAS mutations (45.0%), followed by SF3B1(15.0%), GATA2(15.0%), FLT3-ITD(10.0%), C-Kit/D816(5.0%), and CEBPA(5.0%), without mutation of NPM1(Exon12)or JAK2V617. ConclusionEthnic differences do exist between the Chinese and Western patients with AML-inv(3)/t(3;3), and more attention should be paid involving different ethnic populations and geographic regions.