It was found that the variants rs10740055 of ARID5B and rs6964823 of IKZF1 act individually and additively as risk factors in the development of leukemia in the populations of Jammu and Kashmir in Northern India.
These results identify IKZF1 as a leukemia predisposition gene, and emphasize the importance of germline genetic variation in the development of both familial and sporadic ALL.
In this review, we provide a concise overview on the role of IKZF1 during normal lymphopoiesis and the pathways that contribute to leukemia pathogenesis as a consequence of altered IKZF1 function.
In this issue of Cancer Cell, Churchman et al. add to the list of leukemia predisposition genes with the identification and characterization of germline IKZF1 variants in childhood ALL.
Recent experimental mouse modeling of B-progenitor ALL has shown that IKZF1 alterations have multiple effects, including arresting differentiation, skewing lineage of leukemia from myeloid to lymphoid, and, in Ph+ leukemia, conferring resistance to tyrosine kinase inhibitor (TKI) therapy without abrogating ABL1 inhibition.
Tumor suppressors BTG1 and IKZF1 cooperate during mouse leukemia development and increase relapse risk in B-cell precursor acute lymphoblastic leukemia patients.
The Ikaros gene family, encoding for key transcription factors in hematopoietic development, provides several examples as genetic defects in these genes are associated with the development of different types of leukemia.
The incidence of TET2, ASXL1, CBL, IDH or IKZF1 mutations in these disorders ranges from 0 to 17%; these latter mutations are more common in chronic (TET2, ASXL1, CBL) or juvenile (CBL) myelomonocytic leukemias, mastocytosis (TET2), myelodysplastic syndromes (TET2, ASXL1) and secondary acute myeloid leukemia, including blast-phase MPN (IDH, ASXL1, IKZF1).
We recently identified a poor prognostic subgroup of pediatric BCR-ABL1-negative ALL patients characterized by deletion of IKZF1 (encoding the lymphoid transcription factor IKAROS) and a gene expression signature similar to BCR-ABL1-positive ALL, raising the possibility of activated tyrosine kinase signaling within this leukemia subtype.
While studying Ikaros proteins in childhood acute myeloid leukemia (AML), Ikaros isoform 6 (Ik6) expression was detected in 7 of 10 cases of M4 and M5 leukemia, but in none of the remaining French-American-British subtypes (M2, 8 cases; M7, 6 cases).