We have used a two-step reverse transcriptase polymerase chain reaction (RT-PCR) to detect the transcripts of the chimaeric genes BCR/ABL, ABL/BCR, as well as the normal ABL and BCR genes in 24 CML patients treated with IFN.     ///    "However, 7/10 ABL/BCR mRNA positive patients achieved a major cytogenetic response to IFN. "    ///    The function and clinical significance of the newly discovered ABL/BCR mRNA has not been investigated for a correlation with CML prognosis or response to therapy.     ///    "but of the 13 ABL/BCR mRNA negative patients, only two achieved a major cytogenetic response (P = 0.013). "    ///    "Also, no correlation was found between expression of BCR, ABL or BCR/ABL mRNA and response to treatment with IFN. "    ///    Interferon response in chronic myeloid leukaemia correlates with ABL/BCR expression: a preliminary study.. 