Deletions of EBF1, IKZF1, and CDKN2A/B have an independent adverse prognosis for adolescents and adults with B-precursor ALL, and this suggests that these CNAs should be included in the initial risk assessment of ALL.
One recently identified subtype of pediatric B-precursor acute lymphoblastic leukemia (ALL) has been termed BCR-ABL1-like or Ph-like because of similarity of the gene expression profile to BCR-ABL1 positive ALL suggesting the presence of lesions activating tyrosine kinases, frequent alteration of IKZF1, and poor outcome.
We demonstrated the association of IKZF1 polymorphism rs4132601 T/G with increased risk of ALL among Tunisian pediatric cohort, with altered phenotypic changes among ALL patients.
These classifiers were further validated on an independent high-risk ALL cohort (P = .006) and retainedindependent prognostic significance (P < .001) in the presence of other recently described poor prognostic factors (IKAROS/IKZF1 deletions, JAK mutations, and kinase expression signatures).
We conclude that IKZF1 and TP53 represent relevant prognostic factors that should be considered in future risk assessment of children with relapsed ALL to indicate treatment intensification or intervention.
These findings provide a rationale for the surprisingly high frequency of IKAROS deletions in Ph(+) ALL and identify IKAROS-mediated cell cycle exit as the endpoint of an emerging pathway of pre-B cell receptor-mediated tumor suppression.
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.
Our results demonstrate that the IKAROS promotes PHF2 expression, and suggest that PHF2 <sup>low</sup> expression works with the IKAROS gene deletion to drive oncogenesis of ALL.
Since recently conducted genome-wide association (GWA) studies revealed that the common low-penetrance susceptibility allele at 7p12.2 (IKZF1 gene) confers an increased risk of pediatric ALL, we investigated whether the risk allele at rs4132601 also coexists with well-established prognostic factors, among 508 Polish pediatric patients with newly diagnosed ALL.
The p16(INK4a) (or CDKN2A) gene on 9p21 is a tumor suppressor gene, and deletion thereof is recently recognized as one of the most common genetic abnormalities in ALL.
Telomerase activity was significantly lower in Philadelphia chromosome-negative/IKAROS-deleted (BCR-ABL1(-)/IKAROS(del)) cases compared to Philadelphia chromosome-positive (BCR-ABL1+) BCP-ALLs.
These findings suggest that p16INK4a ICC and deletion analysis provide distinct information about ALL cells and that the simple ICC method may be of prognostic value in standard risk adult ALL.
The gene-expression signature of the group of patients with a poor outcome revealed increased expression of hematopoietic stem-cell genes and reduced expression of B-cell-lineage genes, and it was similar to the signature of BCR-ABL1-positive ALL, another high-risk subtype of ALL with a high frequency of IKZF1 deletion.
Further, by characterizing the roles of translocation-generated fusion genes (TEL-AML 1) and tumor suppressor genes (p15INK4B and p16INK4A) in treatment response, it may be possible to identify new and selective targets and/or treatment strategies for both children and adults with ALL who are refractory to current therapies.
We have performed an exhaustive analysis of TP53, p14, p15, and p16 status in a large series of 143 soft tissue sarcomas, rare tumors accounting for around 1% of all adult cancers, with complex genetics.
We analyzed the expression levels of the Ikaros gene family, Ikaros and Aiolos, in human bone marrow samples from patients with adult acute lymphoblastic leukemia [ALL (n = 46; B-cell ALL = 41; T-cell ALL = 5)].
We analyzed 60 B precursor acute lymphoblastic leukemia (ALL) primary samples and 15 cell lines for homozygous deletions of p16 and p15 genes and mutations of p16 gene.
These data show the coexistence of multiple genetic defects in childhood B-lineage ALL Cell lines with t(12;21) will facilitate the study of TEL-AML1 and AML1-TEL fusion proteins as well as TEL and CDKN2 gene inactivation in leukemia transformation and progression.