Objective To report the coll biology characteristics of the abnormal expression of cCD79a in 7 cases of acute myeloid leukemia ( AML)-M2 with t (8;21 ) ( (q22; q22) selected from 190 AML children since 2005. Methods The characteristics of cell morphology, immunology, cytogenetics, molecular biology ( MICM ) and clinical manifestations in 7 cases of AML-M2 with t( 8; 21 ) ( q22; q22 ) expressing cCD79a abnormally were analyzed. The control group including 20 cases of AML-M2 with t ( 8; 21 ) was detected during the same period. Results The 83 cases of AML-M2 t ( 8 ;21 ) ( q22; q22 ) accounted for 43.7% of 190 continuous childhood AML patients, and the percentage of the cCD79a expression in the 83 cases of AML-M2 t ( 8;21 ) was 8.4% ( 7 cases ). In the cases of AML-M2 with t ( 8; 21 ) ( q22; q22 ) expressing cCD79a abnormally, the bone marrow cell morphology showed the acute myelogenous leukemia M2. The initial cells all increased evidently in the classification. The immunophenotypes were all the expressions of myeloid markers with B-lymphoid. CD34 had high positive expression. There were changes of the chromosome with t ( 8; 21 )( q22; q22 ) , also with the complexly translocation or depletion. The detections of the confluent gene AMLl/ETO were positive. It had achieved good response to combined chemotherapy targeted to both myeloid and lymphoid leukemia. Conclusions t ( 8;21 ) M2 is the most frequent type of childhood AML. It may be related with abnormal expression gene of B lymphocyte phenotype.%目的 报道自2005年来在190例急性髓系白血病(AML)患儿发现的7例t (8;21)(q22;q22)M2亚型中cCD79a异常表达的细胞生物学特征.方法分析7例t (8;21)(q22;q22)M2伴cCD79a异常表达的双表型AML患儿细胞形态学、免疫学、细胞遗传学、分子生物学(MICM)分型及临床特征,取同期诊断的20例t (8;21)的AML-M2患儿作为对照组.结果 83例t (8;21)(q22;q22)AML-M2患儿占同期连续190例AML患儿的43.7%,其中有7例伴有cCD79a异常表达,占8.4%.伴有cCD79a异常表达的t (8;21)(q22;q22)的AML-M2患儿其骨髓细胞形态学均显示为急性粒细胞白血病M2,分类中原始细胞均显著增多;免疫表型均为髓系伴B淋系表达;CD34为高表达阳性;均有t (8;21)(q22;q22)染色体改变,且常伴有染色体复杂易位或缺失等改变;融合基因AML1/ETO检测均为阳性;临床治疗对兼顾髓系和淋系的联合治疗方案效果较好.结论 t(8;21)M2是儿童AML中的最常见类型,易伴有B淋巴细胞表型共表达.
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