Acute myeloid leukemia with isolated del(5q) is associated with IDH1/IDH2 mutations and better prognosis when compared to acute myeloid leukemia with complex karyotype including del(5q).
IDH1 and IDH2 mutations occur frequently in gliomas and acute myeloid leukemia, leading to simultaneous loss and gain of activities in the production of α-ketoglutarate (α-KG) and 2-hydroxyglutarate (2-HG), respectively.
IDH1(R132) and IDH2(R140) mutations are frequently accompanied by normal cytogenetics and NPM1 mutation, whereas IDH2(R172) is frequently the only mutation detected in acute myeloid leukemia.
IDH1/2 mutations occurred in 27 of 31 (87%) AML cases with very high 2-HG, but were observed only in 9 of 31 (29%) patients with moderately high 2-HG, suggesting other genetic or biochemical events may exist in causing 2-HG elevation.
IDH1- and IDH2-mutant primary human AML cells were more sensitive than IDH1/2 wild-type cells to ABT-199, a highly specific BCL-2 inhibitor that is currently in clinical trials for hematologic malignancies, both ex vivo and in xenotransplant models.
IDH1 mutations are closely related to the development and progression of various human cancers, such as glioblastoma, sarcoma, and acute myeloid leukemia.
A high MEBE score, defined as high expression of at least two of the four genes, predicted a significantly shorter overall survival (OS) (HR 2.29, 95 % CI 1.3-4.09, P= .005) and time to AML progression (HR 4.83, 95 % CI 2.01-11.57, P< .001) compared to a low MEBE score in multivariate analysis independent of karyotype, percentage of bone marrow blasts, transfusion dependence, ASXL1, and IDH1 mutation status.
A recent research of cancer has indicated that the mutant of isocitrate dehydrogenase 1 and 2 (IDH1 and 2) genes will induce various cancers, including chondrosarcoma, cholangiocarcinomas, and acute myelogenous leukemia due to the effect of point mutations in the active-site arginine residues of isocitrate dehydrogenase (IDH), such as IDH1/R132, IDH2/R140, and IDH2/R172.
Acquired somatic mutations of IDH1 and IDH2 have recently been reported in some types of brain tumors and a small proportion of acute myeloid leukemia (AML) cases.
Advances in the understanding of the complex mechanisms of AML leukemogenesis have led to the development and recent US Food and Drug Administration (FDA) approval of several targeted therapies: midostaurin and gilteritinib targeting activated FLT3, and ivosidenib and enasidenib targeting mutated IDH1/2.
All subjects with TP53 mutations (n = 21 out of 21 patients) and IDH1 and IDH2 (n = 15 out of 15 patients) mutations eventually developed AML in our study.
Although no new drug has been approved for AML in over four decades, with the exception of gemtuzumab ozogamycin, which was subsequently withdrawn, there is progress on the horizon with the possible regulatory approval soon of agents such as CPX-351 and midostaurin, the Food and Drug Administration "breakthrough" designation granted to venetoclax, and promising agents such as the IDH inhibitors AG-221 and AG-120, the smoothened inhibitor glasdegib and the histone deacetylase inhibitor pracinostat.
Although the first reports have also already emerged describing acquired resistance for these mutant IDH inhibitors, combination treatment might overcome this problem, which could drastically change the treatment landscape of AML over the next few years.