六例伴t（6；9）（p23;q34）急性髓细胞白血病患者的临床和实验研究

A clinical and laboratory study on acute myeloid leukemia with t（6;9）（p23;q34）

目的探讨伴t（6；9）（p23；q34）急性髓细胞白血病（acute myeloid leukemia，AML）患者的临床和生物学特点。方法抽取骨髓细胞按常规制备染色体标本，采用R显带技术进行核型分析；采用标准流式细胞仪和一组单抗检测白血病细胞的抗原表达；应用6号与9号全染色体涂染探针进行染色体荧光原位杂交（fluorescence in situ hybridization，FISH）分析；应用逆转录-PCR技术进行DEK／CAN融合基因和FLT3-ITD突变的检测。结果t（6；9）易位主要见于M2和M4（M24例，M42例）。所有病例的原始细胞均高表达CD13、CD33，其中4例同时表达HLA—DR、3例同时表达CD34和CD117，1例同时表达CD38，1例同时表达CD15。涂染证实6例患者均涉及6和9号染色体的易位，逆转录-PCR检测显示6例患者的DEK／CAN融合基因均为阳性，其中3例同时存在FLT—ITD突变，6例中的3例经治疗后死亡，生存期分别为3、5和6个月，其余病例仍在缓解中。结论t（6；9）（p23；q34）为AML少见的再现性异常，伴有t（6；9）（p23；q34）易位的AML具有独特的生物学特征和临床特点，预后大多不良。

Objective To explore the clinical and laboratory features of 6 cases of acute myeloid leukemia （AML） with t（6;9）（p23;q34）. Methods Chromosome preparation of bone marrow cells was performed with regular method. R-banding by heating using Giemsa banding technique （RHG） was used for karyotype analysis. The immunoprofile was studied by flow cytometry （FCM） using a panel of monoclonal antibodies. Chromosome painting was performed by using whole chromosome paint probes for chromosomes 6 and 9 in all the 6 cases. The expression of fusion gene DEK/CAN and FLT3-ITD mutation were analyzed by reverse transcription-PCR（RT-PCR）. Results The t（6; 9）（p23; q34） was found in all the 6 cases including 4 cases of M2 and 2 cases of M4. Blast cells were positive for CD13 and CD33 in 6 patients, for HLA-DR in 4 patients, for CD34 and CD117 in 3 cases, for CD38 or CD15 each in 1 case, respectively. A reciprocal translocation between chromosome 6 and 9 was confirmed by chromosome painting technique in the 6 cases. The DEK/CAN fusion gene was found in all the 6 cases, FLT3-ITD mutation was detected in three of them. Follow-up showed that 3 patients died with a survival time of 3 months, 5 months and 6 months, respectively. The other three obtained complete remission and are still alive. Conclusion The t（6; 9） （p23 ;q34） is a rare recurrent abnormity. AML with t （6 ;9） （ p23 ; q34） has unique clinical and laboratory features and its prognosis is poor in most cases.