Association between persistence of the BCR/ABL rearrangement and relapse in adult patients with acute lymphoblastic leukaemia

BACKGROUND: The Philadelphia chromosome (Ph') is originated by the t(9;22) which determines the rearrangement BCR/ABL. This rearrangement has been ass ociated with an unfavourable prognosis in patients diagnosed with adult acu te lymphoblastic leukaemia (ALL). PATIENTS AND METHODS: The BCR/ABL gene (p210 and p190) was prospectively st udied by nested RT-PCR in 17 adult patients diagnosed with ALL BCR/ABL-posi tive cases were monitored by RT-PCR and cytogenetic techniques over the tre atment period (LAL-93 AR protocol). RESULTS: BCR/ABL mRNA was detected in 8 out the 17 patients studied (47%). The Ph' chromosome was detected in 4 cases. Follow-up was completed in 6 ou t of the 8 BCR/ABL positive cases. PCR only became negative in one patient. The 5 patients with persistently positive BCR/ABL relapsed, whereas the ca se which became negative was still in complete remission after 24 months fo llow-up. In 3 out of the 4 Ph' positive patients, the karyotype was normal after induction therapy. CONCLUSIONS: This study clearly demonstrates the usefulness of molecular an alysis in the diagnosis and follow-up of ALL compared with conventional cyt ogenetic techniques. The importance of molecular analysis to assess the eff icacy of the treatment used has been emphasized and the poor evolution of B CR/ABL-positive patients has been confirmed.