RT-PCR monitoring of BCR-ABC mRNA after allogeneic bone marrow transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia

BACKGROUND: Allogeneic bone marrow transplantation (BMT) has been performed as one mode of cure-oriented therapy for Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL-Ph' positive). However, the clinical sign ificance of the residual BCR-ABL-positive clones after BMT is still controv ersial. PATIENTS AND METHODS: The BCR-ABL gene (p210 and p190) was prospectively st udied by nested RT-PCR in 8 ALL-Ph' positive patients undergoing BMT. RESULTS: All patients received BMT at the time of clinical remission (CR). However, minimal residual disease (MRD) was detected in 7 of them. MRD dete cted just before BMT seems to be eradicated by BMT protocol. Four patients remained in CR and did not show BCR-ABL transcripts. Other 4 patients, rela psed, demonstrating MRD, which preceded recurrence by a median time of 6 we eks. Three relapsed patients showed p190 transcript and only one, p210 type . CONCLUSIONS: The RT-PCR assay appears to be a useful test for predicting at high risk of relapse after BMT and may identify patients who might benefit from therapeutic interventions. The finding that the expression of p190 BC R-ABL may carry an especially high risk of relapse suggests a different cli nical and biologic behaviour between p190 and p210 BCR-ABL.