Merchant Shakil, Schlette Ellen, Sanger Warren, Lai Raymond, Medeiros L Jeffrey
Division of Pathology and Laboratory Medicine, The University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
Arch Pathol Lab Med. 2003 Mar;127(3):305-9. doi: 10.5858/2003-127-0305-MBCLWM.
The molecular genetic events involved in the pathogenesis of mature B-cell leukemias with more than 55% prolymphocytes are not well characterized. We have encountered 2 such cases in which conventional cytogenetic analysis identified Burkitt lymphoma-type chromosomal translocations involving 8q24.
To assess these 2 cases for involvement of the c-myc gene using fluorescence in situ hybridization analysis with probes specific for the c-myc and immunoglobulin heavy-chain (IgH) genes.
In both cases, conventional cytogenetic analysis demonstrated complex karyotypes, including chromosomal translocations involving 8q24. In case 1, a case of de novo prolymphocytic leukemia, the t(8;14)(q24;q32) was detected. In case 2, a case of chronic lymphocytic leukemia in prolymphocytoid transformation, the t(8;22)(q24;q11) was identified. Fluorescence in situ hybridization studies showed c-myc/IgH fusion signals in case 1, proving the presence of the t(8;14). Split c-myc signals without fusion to IgH were observed in case 2, proving c-myc gene rearrangement and consistent with the t(8;22).
These results suggest that c-myc gene alterations may be involved in the pathogenesis of a subset of mature B-cell leukemias with more than 55% prolymphocytes.
成熟B细胞白血病发病机制中涉及的分子遗传学事件，在原淋巴细胞比例超过55%的情况下尚未得到充分表征。我们遇到了2例这样的病例，其中常规细胞遗传学分析鉴定出涉及8q24的伯基特淋巴瘤型染色体易位。
使用针对c-myc和免疫球蛋白重链（IgH）基因的特异性探针，通过荧光原位杂交分析评估这2例病例中c-myc基因的受累情况。
在这2例病例中，常规细胞遗传学分析均显示出复杂的核型，包括涉及8q24的染色体易位。病例1为一例新发原淋巴细胞白血病，检测到t(8;14)(q24;q32)。病例2为一例处于原淋巴细胞样转化的慢性淋巴细胞白血病，鉴定出t(8;22)(q24;q11)。荧光原位杂交研究在病例1中显示出c-myc/IgH融合信号，证实存在t(8;14)。在病例2中观察到c-myc信号分离且未与IgH融合，证实c-myc基因重排，与t(8;22)一致。
这些结果表明，c-myc基因改变可能参与了原淋巴细胞比例超过55%的一部分成熟B细胞白血病的发病机制。
