Multiple molecular abnormalities in Ph1 chromosome positive acute lymphoblastic leukaemia

Area of Science:

• Hematology
• Molecular Biology
• Oncology

Background:

• The Philadelphia chromosome (Ph1) is a hallmark of chronic myelogenous leukemia (CML), present in 95% of patients.
• Ph1 is also observed in 5-25% of pediatric and adult acute lymphoblastic leukemia (ALL) cases, prompting investigation into disease relationships.

Purpose of the Study:

• To investigate the molecular events involving BCR and c-ABL genes in Ph1-positive ALL patients.
• To determine the relationship between Ph1-positive ALL and CML at a molecular level.

Main Methods:

• Analysis of molecular abnormalities related to BCR and c-ABL gene rearrangements.
• Study of gene expression and translocations in five patients with Ph1-positive ALL.

Main Results:

• Four out of five ALL patients with the Ph1 chromosome (or probable Ph1) exhibited molecular abnormalities identical to those found in CML, suggesting a common molecular basis.
• One patient with Ph1 and c-ABL translocation lacked the typical CML-associated molecular changes but showed abnormal c-ABL gene transcription independent of BCR.

Conclusions:

• Ph1-positive ALL represents a heterogeneous group of diseases.
• In some Ph1-positive ALL patients, the molecular pathology mirrors CML.
• Other Ph1-positive ALL cases involve c-ABL but through distinct molecular mechanisms, indicating varied disease pathways.