Choughule A, Polampalli S, Amre P, Shinde S, Banavali S, Prabhash K, Nair R, Subramanian P G, Gujral S, Parikh P M
Molecular Biology Laboratory, Department of Medical Oncology, Tata Memorial Hospital, Mumbai, Maharashtra, India.
Genet Mol Res. 2009 Jan 6;8(1):1-7. doi: 10.4238/vol8-1gmr488.
Acute promyelocytic leukemia (APL) is characterized by a reciprocal translocation, t(15;17)(q22;q11-21), resulting in the fusion of the promyelocytic leukemia (PML) and retinoic acid receptor alpha (RARalpha) genes. Using conventional cytogenetic methods, these translocations are normally detected in about 70-90% of patients; most negative results are due to technical problems or cryptic variants. These masked PML/RARalpha fusions can be identified by molecular analyses, such as reverse transcriptase-polymerase chain reaction (RT-PCR) or fluorescence in situ hybridization (FISH). Approximately 5 to 10% of all APL cases reported do not show PML/RARalpha fusion transcripts, even with dual-colored FISH. We report three of 40 diagnosed APL cases that showed morphological, cytochemical, and immunophenotypic features of hypergranular APL, but did not show a PML/RARalpha fusion signal or any of its variants, on FISH. All cases were identified by RT-PCR, which was further confirmed by cDNA sequencing. Conventional karyotyping showed other clonal aberrations in these cases, but failed to show t(15;17) or any other variants or complex translocations.
急性早幼粒细胞白血病（APL）的特征是存在一种相互易位，即t(15;17)(q22;q11-21)，导致早幼粒细胞白血病（PML）基因与维甲酸受体α（RARα）基因融合。使用传统细胞遗传学方法，通常在约70-90%的患者中检测到这些易位；大多数阴性结果是由于技术问题或隐匿性变异。这些隐匿的PML/RARα融合可通过分子分析方法来识别，如逆转录聚合酶链反应（RT-PCR）或荧光原位杂交（FISH）。即使采用双色FISH检测，所有报道的APL病例中仍有大约5%至10%未显示PML/RARα融合转录本。我们报告了40例确诊的APL病例中的3例，这些病例在形态学、细胞化学和免疫表型上表现为颗粒增多型APL的特征，但在FISH检测中未显示PML/RARα融合信号或其任何变异形式。所有病例均通过RT-PCR鉴定，并经cDNA测序进一步证实。传统核型分析显示这些病例存在其他克隆性异常，但未显示t(15;17)或任何其他变异或复杂易位。
