Metaphase fluorescence in situ hybridization (FISH) in the follow-up of 60 patients with haemopoietic malignancies.

Metaphase DNA fluorescence in situ hybridization (metaphase-FISH) was performed on follow-up samples from 60 patients suffering from haemopoietic malignancies (acute and chronic myeloid leukaemia, acute lymphoblastic leukaemia, non-Hodgkin's lymphoma and myelodysplastic syndrome). All patients had clonal chromosomal trisomies or translocations at diagnosis, and were treated by bone marrow transplantation (BMT), chemotherapy (CT) or interferon-alpha therapy. Metaphase-FISH was performed during therapy-induced complete haematological remission (CR) (BMT and CT patients) using biotin-labelled whole chromosome paint probes. 28% of all patients in CR were shown by FISH to have abnormal metaphase cells, and 62% of this group suffered a clinical relapse. Of those with negative FISH results (72%), 12% relapsed. In three CML patients treated with BMT a small population of t(9;22)-positive cells was demonstrated. These cells disappeared during follow-up without causing a relapse. One ALL patient had abnormal cells a short time after start of therapy but was also later found FISH-negative. Furthermore, we demonstrated that metaphase-FISH is a suitable method for quantifying the proportion of abnormal cells in CML patients during interferon-alpha therapy. Metaphase-FISH was also employed to detect a local relapse in an ALL patient. Thus, metaphase-FISH was found reliable and sensitive for detection of minimal residual disease in patients with haemopoietic malignancies.