SLC22A4 is an organic cation transporter with unknown physiological function, and RUNX1 is a hematological transcriptional regulator that has been shown to be responsible for acute myelogenic leukemia.
This makes an interesting contrast to the case of familial and sporadic leukemias mediated by RUNX1 mutations, in which mutants acting in a dominant negative manner have been suggested to confer a higher propensity to develop leukemia.
Specific gene activation (N-myc, evi-1) or fusion genes such as the alpha retinoic acid receptor (alpha RAR) and pml have been identified as the specific cause of some cases of leukemia.
The AML1 ( acute myeloid leukemia 1) gene, a necessary prerequisite of embryonic hematopoiesis and a critical regulator of normal hematopoietic development, is one of the most frequently mutated genes in human leukemia, involving over 50 chromosome translocations and over 20 partner genes.
A hematological cancer panel assay indicated that EZH1/2 dual inhibitor has efficacy against some lymphomas, multiple myeloma, and leukemia with fusion genes such as MLL-AF9, MLL-AF4, and AML1-ETO.
The fusion gene produces a chimeric transcription factor that suppresses the expression of AML1-target genes via the MTG8 part of the chimeric protein, which is thought to be the primary cause of leukemia.
Presence of ETV6/RUNX1 alone is usually not sufficient for leukemia onset, and additional genetic alterations have to occur in ETV6/RUNX1-positive cells to cause transformation.
Conditional deletion of Runx1 in adult mice results in an increase of hematopoietic stem cells (HSCs), which serve as target cells for leukemia; however, Runx1(-/-) mice do not develop spontaneous leukemia.
AML1-ETO-W692A loses N-CoR binding at NHR4, displays attenuated transcriptional repression ability and decreased cellular dysregulation, and promotes leukemia in vivo.
AML1 amplification was found in a 13-year-old patient with AML M4/M5 leukemia that occurred 5 years after she had been diagnosed with common B-cell ALL.
In this study, three leukemic cell lines were investigated: Kasumi-1 and SKNO-1 (two acute myeloid leukemia (AML) cell lines carrying the (8;21)-chromosomal translocation, resulting in the expression of the leukemia-specific fusion protein AML1-eight-twenty-one) and REH, an acute lymphoblastic leukemia cell line with the (12;21)-chromosomal translocation and expression of translocation ETS-like leukemia-AML1.
ETV6/RUNX1 and MLL aberration clone size in these cases was suggestive of ETV6/RUNX1 as an early primary event, originating in the embryonic or infant stage and developing into leukemia by later acquisition of MLL aberration, ETV6 loss, and ETV6/RUNX1 duplication as secondary events.
Uncommon chromosome changes may lead to the identification of leukemogenetic factors associated with t(8;21) since the AML1/RUNX1-ETO fusion gene resulting from the translocation is thought to be unable alone to induce leukemia.
Based on this observation we concluded that individuals with a constitutional trisomy 21 may have the similar likelihood to develop a TEL/AML1+ leukemia as BCP ALL patients without this specific predisposingfactor.
Overexpressed Runx1 transgene in BXH2 mice resulted in shortening of the latency of leukemia with increased frequency of megakaryoblastic leukemia, suggesting that increased Runx1 dosage is leukemogenic in myeloid lineage.
Alterations of the ets family transcription factor ETV6 (TEL) and the RUNT domain transcription factor RUNX1 (AML1) play pivotal roles in the leukemogenesis of various types of leukemia.