Assessment of BCR-ABL fusion gene testing or quantification using RT-PCR in the diagnosis and therapeutic follow-up of chronic myeloid leukaemias and acute lymphoblastic leukaemias - INAHTA Brief

The BCR-ABL fusion gene, also called the Philadelphia gene or chromosome Ph1, is the result of a reciprocal translocation between chromosomes 9 and 22. The BCR-ABL fusion gene codes for a fusion protein with a deregulated tyrosine kinase activity, which activates various mechanisms involved in cell multiplication.

The BCR-ABL fusion gene is present in all chronic myeloid leukaemias (CML), 3 to 5% of acute lymphoblastic leukaemias (ALL) in children and between 15 to 30% of ALL in adults. Therefore, routine testing is done when CML or ALL is suspected.

The BCR-ABL fusion gene is evidenced by cytogenetics (karyotype), molecular cytogenetics (FISH), or by RT-PCR. BCR-ABL fusion transcript can also be quantified by quantitative PCR (RT-qPCR).

Currently, only BCR-ABL fusion gene testing is included in the list of the laboratory medicine procedures reimbursement by the health insurance system in France (NABM). BCR-ABL transcript testing by molecular biology is included in the additional list of laboratory medicine and anatomo-cytopathology procedures outside of the nomenclature.