A triple‐probe FISH screening strategy for risk‐stratified therapy of acute lymphoblastic leukaemia in low‐resource settings

Abstract

Karyotyping along with a 3-probe fluorescence in situ hybridization (FISH) strategy was used to risk stratify therapy in 303 children with B-cell precursor acute lymphoblastic leukaemia. Of the 166 patients risk stratified, karyotype identified 91 (55%). FISH identified all karyotypes accurately, with the exception of hypodiploidy, and risk stratified an additional 75 patients. The frequency of ETV6-RUNX1 is lower and high hyperdiploidy, higher than reported in the west. An adapted 3-probe FISH strategy identified two patients with ETV6-ABL1 fusion who received imatinib. In limited-resource settings, a 3-probe FISH approach provides a practical approach for risk-stratified therapy in childhood ALL.

Blast size‐specific flowcytometric ploidy assessment using FxCycleTM Violet dye and its correlation with conventional cytogenetic ploidy in pediatric precursor B‐lineage acute lymphoblastic leukemia patients

“…This higher concordance is due to an increased number of masked CG high‐hyperdiploidies identified by CEP‐based i‐FISH strategies in the above studies. In this regard, among our six FCM high‐hyperdiploid patients who were CG‐diploid, simultaneous implementation of i‐FISH CEP strategy for ploidy identification might have revealed masked high‐hyperdiploidy in at least three patients showing extra RUNX1 signals 5 . However, such reclassification was not possible in the current study as i‐FISH with CEP was not attempted to assess ploidy status.…”

“…Interphase FISH (i‐FISH) strategies using centromere enumeration probes (CEP) can aid in ploidy assessment, especially in identifying masked‐hyperdiploidies (diploid by CG but hyperdiploid by FISH) and masked‐hypodiploidies (endo‐duplicated near‐haploid/low‐hypodiploid blasts misidentified as high‐hyperdiploid/near‐triploid by CG). However, i‐FISH is not sensitive enough to identify near‐haploidy, low‐hypodiploidy, and near‐triploidy 4‐7 . Due to these reasons, conventional cytogenetics, though laborious and time‐consuming, is the widely used technique to identify aneuploidies.…”

Experience of Paediatric Acute Lymphoblastic Leukemia Service in A Newly Established Haemato-Oncology Center in Bangladesh: Opportunities and Challenges

“…Cytogenetic studies include fluorescence in situ hybridization (FISH) assays for ETV6-RUNX1; BCR-ABL1; KMT2A rearrangements; iAMP21; TCF3-HLF was done for all maintenance patient whose treatment were initiated at TMC. 13 As complete cytogenetic testing by FISH is not available in Bangladesh, we did only RT-PCR method for BCR-ABL in newly diagnosed patient at our center. Only one of newly diagnosed patient had done cytogenetic studies for other translocations including t (12;21) Early treatment response was determined by prednisolone response (prednisolone good responder [PGR] and prednisolone poor responder [PPR] if they had <1000 blasts/PL in peripheral blood and >1000 blasts/PL in peripheral blood after 1 week of steroid prephase respectively) and minimal residual disease (MRD) estimation after 5 weeks of induction treatment.…”

Protocol for ICiCLe-ALL-14 (InPOG-ALL-15-01): a prospective, risk stratified, randomised, multicentre, open label, controlled therapeutic trial for newly diagnosed childhood acute lymphoblastic leukaemia in India

“…cranial nerve palsies). Cytogenetic studies include fluorescence in situ hybridisation (FISH) [ 26 ] assays for recurrent gene fusions, rearrangements and amplifications ( ETV6 - RUNX1 ; BCR - ABL1 ; KMT2A rearrangements; other ABL -class rearrangements; intrachromosomal amplification of chromosome 21 [iAMP21]; TCF3 - HLF ) and screening for aneuploidies (specifically hypodiploid ALL, modal chromosome number < 40) by DNA ploidy analysis (flow cytometry) and/or conventional karyotyping. Treatment response is assessed by evaluating the prednisolone response [ 27 ] and by assessing the remission status and levels of MRD in the bone marrow following completion of the induction treatment phase.…”