BCR/ABL1 fusion transcripts generated from alternative splicing: implications for future targeted therapies in Ph+ leukaemias

The Genetic Variants of IKZF1 Gene Linked with the Growing Risk of Childhood Acute Lymphoblastic Leukaemia

BACKGROUND

The zinc finger protein IKAROS (IKZF1) is an essential transcription factor in haematopoiesis that is involved primarily in lymphoid tissue differentiation. Many studies have indicated that IKZF1 alterations may be associated with acute lymphoblastic leukaemia, but the results remain controversial.

OBJECTIVE

We aimed to investigate the association of the rs4132601 T/G and rs10272724 T/C IKZF1 gene polymorphisms with the risk of childhood acute lymphoblastic leukaemia and to determine whether these genetic variants affect the clinical parameters and the iron profiles of these children cohort.

METHODS

This case control study was conducted on 170 Egyptian children comprising of two groups: group (I) included 90 children diagnosed with acute lymphoblastic leukaemia and group (II) comprised of 80 ages and sex-matched healthy control children. The studied polymorphisms were genotyped using PCR restriction fragment length polymorphism (PCR-RFLP).

RESULTS

A higher frequency of the mutant GG genotype and G allele of rs4132601 was found in the patient group than in the control group. The results also showed a significant difference among the rs10272724 genotypes, with a higher frequency of the mutant CC genotype and C allele in the patients than in controls. The mutant GG genotype of rs4132601 and the mutant CC genotype of rs10272724 were associated with a higher serum ferritin level and transferrin saturation and an older age at diagnosis of acute lymphoblastic leukaemia than the other genotypes.

CONCLUSION

IKZF1 rs4132601 and rs10272724 could be considered significant risk contributors to childhood acute lymphoblastic leukaemia and may impact the iron profiles in these children.

Past, present, and future of Bcr-Abl inhibitors: from chemical development to clinical efficacy

Bcr-Abl inhibitors paved the way of targeted therapy epoch. Imatinib was the first tyrosine kinase inhibitor to be discovered with high specificity for Bcr-Abl protein resulting from t(9, 22)-derived Philadelphia chromosome. Although the specific targeting of that oncoprotein, several Bcr-Abl-dependent and Bcr-Abl-independent mechanisms of resistance to imatinib arose after becoming first-line therapy in chronic myelogenous leukemia (CML) treatment.Consequently, new specific drugs, namely dasatinib, nilotinib, bosutinib, and ponatinib, were rationally designed and approved for clinic to override resistances. Imatinib fine mechanisms of action had been elucidated to rationally develop those second- and third-generation inhibitors. Crystallographic and structure-activity relationship analysis, jointly to clinical data, were pivotal to shed light on this topic. More recently, preclinical evidence on bafetinib, rebastinib, tozasertib, danusertib, HG-7-85-01, GNF-2, and 1,3,4-thiadiazole derivatives lay promising foundations for better inhibitors to be approved for clinic in the near future.Notably, structural mechanisms of action and drug design exemplified by Bcr-Abl inhibitors have broad relevance to both break through resistances in CML treatment and develop inhibitors against other kinases as targeted chemotherapeutics.

Characterization of a novel variant BCR-ABL1 fusion transcript in a patient with chronic myeloid leukemia: Implications for molecular monitoring

Molecular monitoring of BCR-ABL1 transcript levels using quantitative polymerase chain reaction is an essential part of the modern management of chronic myeloid leukemia patients treated with tyrosine kinase inhibitors. Establishing the diagnostic BCR-ABL1 fusion transcript is necessary in order to select appropriate primers and probes for such monitoring. A case is described in which quantitative polymerase chain reaction failed to detect the presence of BCR-ABL1 fusion transcript in a Philadelphia chromosome-positive chronic myeloid leukemia patient. Further investigation demonstrated a novel in-frame BCR-ABL1 fusion transcript with a breakpoint in BCR exon 13 and insertion of a sequence of ABL1 intron 1, therefore enabling subsequent molecular monitoring. This case highlights the requirement for characterization of the BCR-ABL1 transcript type at chronic myeloid leukemia diagnosis. Issues concerning standardized methodological approaches and interpretation of transcript levels in such rare cases are discussed.