Zhao Weiqiang, Claxton David F, Medeiros L Jeffrey, Lu Di, Vadhan-Raj Saroj, Kantarjian Hagop M, Nguyen Martin H, Bueso-Ramos Carlos E
Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Am J Surg Pathol. 2006 Nov;30(11):1436-44. doi: 10.1097/01.pas.0000213301.19273.66.
The inv(16)(p13q22) or, less commonly the t(16;16)(p13;q22), is characteristic of acute myeloid leukemia (AML) with abnormal bone marrow eosinophils, also known as AML-M4Eo. This abnormality creates a fusion gene, 5' core binding factor beta (CBF-beta) gene and the 3' MYH11 gene, the latter encoding smooth muscle myosin heavy chain gene (SMMHC). Detection of this abnormality is important for diagnosis and is most commonly done by cytogenetics or molecular methods. In this study, we determined the utility of immunohistochemical and immunofluorescence methods using a rabbit polyclonal antibody (AH107) against the C-terminus of the CBFbeta-SMMHC chimeric protein for diagnosis of AML-M4Eo. Thirty-nine AML-M4Eo cases and 55 cases of other types of AML were evaluated. Immunohistochemical analysis of routinely processed paraffin-embedded bone marrow sections showed that CBFbeta-SMMHC staining is predominantly nuclear in all cases of AML-M4Eo and is not nuclear in other AML types. Four cases of AML-M4Eo double-stained for CBFbeta-SMMHC and CD34 showed the fusion protein in CD34-positive blasts. Indirect immunofluorescence analysis of fresh bone marrow aspirate smears showed that AML-M4Eo blasts have a distinct nuclear microgranular or fine-speckled pattern of staining, with or without faint cytoplasmic staining. By contrast, other types of AML and normal bone marrow specimens were either negative or had a nonspecific pattern of staining. In summary, immunostaining for CBFbeta-SMMHC using either immunohistochemical or immunofluorescense analysis as described here reveals a distinctive pattern of staining for AML-M4Eo. This approach is a specific, reliable, and convenient alternative to cytogenetic and molecular methods for the diagnosis of AML-M4Eo and may be particularly helpful in cases with indeterminate histologic features or in cases in which cytogenetic and molecular studies are either uninformative or not available.
inv(16)(p13q22)，或者较罕见的t(16;16)(p13;q22)，是伴有异常骨髓嗜酸性粒细胞的急性髓系白血病（AML）的特征性表现，也称为AML-M4Eo。这种异常产生了一个融合基因，即5'核心结合因子β（CBF-β）基因和3'MYH11基因，后者编码平滑肌肌球蛋白重链基因（SMMHC）。检测这种异常对诊断很重要，最常用的方法是细胞遗传学或分子方法。在本研究中，我们确定了使用针对CBFβ-SMMHC嵌合蛋白C端的兔多克隆抗体（AH107）进行免疫组织化学和免疫荧光方法诊断AML-M4Eo的实用性。评估了39例AML-M4Eo病例和55例其他类型的AML病例。对常规处理的石蜡包埋骨髓切片进行免疫组织化学分析显示，在所有AML-M4Eo病例中，CBFβ-SMMHC染色主要位于细胞核，而在其他AML类型中则不在细胞核。4例AML-M4Eo病例同时进行CBFβ-SMMHC和CD34双重染色，结果显示融合蛋白存在于CD34阳性的原始细胞中。对新鲜骨髓穿刺涂片进行间接免疫荧光分析显示，AML-M4Eo原始细胞具有独特的核微颗粒状或细斑点状染色模式，有或无微弱的细胞质染色。相比之下，其他类型的AML和正常骨髓标本要么为阴性，要么具有非特异性染色模式。总之，使用本文所述的免疫组织化学或免疫荧光分析对CBFβ-SMMHC进行免疫染色可显示AML-M4Eo独特的染色模式。这种方法是诊断AML-M4Eo的细胞遗传学和分子方法的一种特异性、可靠且便捷的替代方法，对于组织学特征不明确的病例或细胞遗传学和分子研究无信息或无法进行的病例可能特别有帮助。
