A 74-year-old man was previously diagnosed with BCR-ABL1-positive pre-B cell acute lymphoblastic leukaemia (pre-B ALL) based on bone marrow cytology, flow cytometry, cytogenetics and fluorescent in situ hybridisation findings.
It is not clear how ABL1 deletion affects leukemogenesis; however, it is plausible that ABL1 deletion without BCR/ABL1 rearrangement is a rare but recurrent genetic abnormality in precursor B-ALL patients.
Some cases of pre-B cell acute lymphoblastic leukemia (pre-B-ALL) are caused by the Philadelphia (Ph) chromosome-encoded BCR-ABL oncogene, and these tend to have a poor prognosis.
Comparing genome-wide gene expression profiles of BCR-ABL1+ pre-B ALL and normal bone marrow pre-B cells by serial analysis of gene expression, many genes involved in pre-B cell receptor signaling are silenced in the leukemia cells.
In this prospective study, samples from 478 patients with CD10(+) B-cell precursor ALL (c-ALL and pre-B ALL) underwent BCR-ABL reverse transcription-polymerase chain reaction (RT-PCR) analysis with double testing of positive samples.
Pre-B acute lymphoblastic leukemia with b3a2 (p210) and e1a2 (p190) BCR-ABL fusion transcripts relapsing as chronic myelogenous leukemia with a less differentiated b3a2 (p210) clone.
Immunophenotypic studies at diagnosis in 21 BCR/ABL-positive children identified common ALL in 16 patients (76.2%), pre-B-ALL in four (19.0%), and an early T-lineage ALL in one (4.8%).