Chinese Journal of Cancer the Nanfang Hospital, Southern Medical University between May 2004 and May 2009 were selected. Of these patients, 26 were male and five female, with a median age of 35 years (age range 12 41 years). All these patients were confirmed and staged by cytomorphology, cell histochemistry, cytogenetics and molecular genetics, and underwent alloHSCT in Nanfang Hospital within one year after being diagnosed. Informed consent about alloHSCT was obtained from all the patients. Before transplantation, 22 patients were at chronic phase and nine at blast crisis or acceleration phase. Among them, 24 patients were treated with hydroxyurea and the other seven with imatinib. After the transplantation, FISH and RQPCR were performed to detect BCRABL fusion gene at varied time points. Followup time after transplantation ranged from 3 to 48 months. A total of 159 bone marrow samples were collected at different time points before and after the transplantation.

A dualcolor dualfusion DNA probe provided by Vysis was used for the detection. According to the FISH operation procedures for interphase cells in the hematology laboratory of Nanfang Hospital, the samples were treated, denatured, hybridized and eluted 2. Hybridization signals were observed under fluorescent microscope Nikon E600 with a tricolor filter (DAPI/TRITC/FITC); red signal indicated BCR, green signal indicated ABL, while yellow signal indicated BCRABL fusion. In the interphasic nucleus of a normal cell, four hybridization signals could be seen, including two red and two green signals, and red signals were well separated from green ones, while in interphasic nucleus with BCRABL expression, one red and one green hybridization signals and one yellow fusion signal could be found. Images were taken by a highresolution CCD (by COHU) and analyzed by a fluorescent image analyzing system (by PSI, England). A total of 1000 cells were counted for each sample. A BCRABL positive cell percentage of 臆 3% was considered as a background signal 3.