RESUMO
Objective:To determine the derivative chromosome 9 by the method of detecting the ASS gene,and to explore the relationship between the deletion of derivative chromosome 9 and the efficacy and prognosis of the chronic myeloid leukemia (CML)patients. Methods:The materials of 34 CML patients with positive BCR-ABL fusion gene whose ASS genes were detected were retrospectively analyzed. All patients were treated with Extra-signal (ES)probe to detect the derivative chromosome 9.All patients were divided into two groups according to whether they carried the derivative chromosome 9.The blastic phase or the accelerated phase rates in two groups were compared by using Fisher exact probability. Results:All patients were detected by FISH (BCR-ABL ES probe),and all the BCR-ABL fusion signals were positive.6 of 34 patients were found the deletion of ASS gene, among them 1 case blonged to chronic phase,and 5 cases developed into blastic phase or accelerated phase. In the patients without ASS gene deletion,there were 22 cases in chronic phase,and 6 cases in plastic phase or accelerate phase,there was significant difference of blastic phase rate/accelated phase rate between them (P 0.05 ). Conclusion:The CML patients with derivative chromosome 9 (ASS gene deletion)prone to get disease progression, and have a higher proportion in the blastic phase or accelerated phase patients.Derivative chromosome 9 is related to the bad treatment efficacy of TKI and the poor prognosis of CML.
RESUMO
BACKGROUND: The complementary ABL-BCR gene rearrangement is formed at chromosome 9 parallel to the Ph chromosome at der(22)t(9;22), which has been found deleted in a minority of chronic myelogenous leukemia (CML) patients. This study was designed to analyze the deletion status of ABL and/or BCR on derivative chromosome 9 and to evaluate the prognostic significance of the deletion of these genes in CML. METHODS: We studied 79 patients who were diagnosed as CML at Seoul National University Hospital between January 1997 and February 2002. The deletion status of ABL and BCR on derivative chromosome 9 was investigated by interphase fluorescent in situ hybridization (FISH) method. RESULTS: ABL deletion was detected in 14 (17.7%) patients and BCR deletion was observed in 8 patients (10.1%). Event-free survival time of the patients with ABL and/or BCR deletion (19.0%) was shorter than that of the patients without any deletion of these two genes (median, 40.0 months vs. 92.0 months)(P=0.027). Twenty seven patients progressed to blast crisis in this period. The period to blast crisis was also shorter in 8 patients with ABL and/or BCR deletion than in 19 patients without any gene deletion (P=0.044). The b2a2 mRNA type was more frequent in the patients with ABL deletion only than in the patients without any gene deletion (P=0.034). CONCLUSIONS: Event-free survival time and the period to blast crisis were significantly shorter in patients with deletion of ABL and/or BCR on derivative chromosome 9. ABL and/or BCR deletion can be a significant prognostic marker that indicates rapid disease progression.