RESUMO
BACKGROUND: The effective treatment of hematologic malignancies depends upon application of different therapeutic strategies by selecting patients known as the high risk group and the detection of malignant cells that can not be distinguished during following-up. We compared the results of G-banding and fluorescence in situ hybridization (FISH), which are used most frequently in detecting genetic changes, with the respect to investigating the discrepancies between these methods. METHODS: G-banding and FISH were performed on 919 consecutive specimens from 304 patients with hematologic malignancies. As for FISH, we covered most of the more frequent gene-tic changes, using 18 types of FISH probe. RESULTS: The average discrepancy between G-banding and FISH was 8.6% with a discrepancy at initial diagnosis of 6.0% and at follow-up of 11.9%, indicating greater discrepancy at follow-up after treatment. The chromosomal changes with especially large discrepancies were TEL/AML1, BCR/ABL & del(5q) (22.4%, 18.1%, and 16.2%, respectively). According to each disease, the discrepancies in acute biphenotypic leukemia (33.3%), acute lymphoblastic leukemia (14.7%), and chronic myelogenous leukemia (9.6%) were larger than average discrepancy. CONCLUSTIONS: We concluded that application of FISH is effective for detecting genetic changes in hematologic malignancies. Once genetic changes are detected, follow-up with FISH would be especially effective for making an accurate assessment of the likelihood of complete remission and recurrence.