There was a significant correlation between the BCR-ABL transcript detected at diagnosis by RQ-PCR and that retrospectively detected by FISH from the aged BM smears at diagnosis (r = 0.870; P = 0.035). Conclusion. Archival methanol-fixed marrow and peripheral blood smears can be used to detect the BCR-ABL transcript for CML diagnosis. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.