CASC15 is a conserved lncRNA that was upregulated in pediatric B-acute lymphoblastic leukemia (B-ALL) with t (12; 21) as well as pediatric acute myeloid leukemia (AML) with t (8; 21), both of which are associated with relatively better prognosis.
Impaired differentiation is prominently observed in the pro-B-cell compartment, resulting in an proportional increase in early progenitors in vivo, consistent with the t(12;21) ALL phenotype.
TEL is frequently disrupted by chromosomal translocations such as the t(12;21), which is associated with nearly one-fourth of pediatric B cell acute lymphoblastic leukemia.
The TEL-AML1 fusion which results from the t(12;21) rearrangement in childhood B-precursor acute lymphoblastic leukaemia (B-precursor ALL) is often accompanied by loss of the untranslocated TEL allele.
We conclude that childhood precursor B-ALL carrying the t(12;21) translocation display characteristic phenotypic features which could provide a rapid, simple, sensitive and specific screening method to select for those cases that should undergo confirmatory molecular analysis.
Since the ider(21) is cytogenetically indistinguishable from i(21)(q10) and idic(21)(p11), changes associated with similar clinical features as the t(12;21), i.e. pre-B-cell ALL and age 1-10 years, we suggest that all ALL displaying these changes should be tested for ETV6/CBFA2 fusion transcript.