小细胞恶性肿瘤MyoD1、myogenin的染色敏感性和特异性

Specificity and sensitivity of MyoD1 and myogenin in small cell tumors

目的 :研究肌源性调节蛋白在小细胞恶性肿瘤病理诊断与鉴别诊断中的作用。方法 :应用免疫组化S P法 ,对 5 6例小细胞恶性肿瘤 ,包括 19例的胚胎性横纹肌肉瘤、6例的腺泡状横纹肌肉瘤、3例的Wilm瘤、14例的Ewing肉瘤 /PNETs、14例的神经母细胞瘤以及 4例的多形性横纹肌肉瘤行MyoD1、myogenin、MSA、desmin、myoglobin和CD99染色标记。 结果 :MyoD1和myogenin阳性核染色分别见于 2 1/ 2 9(72 4 1% )和 2 0 / 2 9(6 8 97% )的横纹肌肉瘤。除多形性横纹肌肉瘤外 ,4例MyoD1与5例myogenin核染色阴性者没有重叠。 3例Wilm瘤中 2例幼年型MyoD1核染色阳性 ,而myogenin只有 1例核染色阳性 ,另1例成年型Wilm瘤二者均染色阴性。 14例的Ewing肉瘤 /PNETs和 14例的神经母细胞瘤未见核阳性染色。MyoD1和myo genin核阳性染色与横纹肌肉瘤的分化程度呈负相关 ,在较小的原始肿瘤细胞中MyoD1和myogenin核染色比例较高 ,而具有骨骼肌分化的、较大的横纹肌母细胞核阳性染色比例较低。在横纹肌肉瘤中 ,MyoD1阳性核染色的肿瘤细胞比myogenin多 ,myogenin多在小的肿瘤细胞核上染色 ,而MyoD1无论小的原始肿瘤细胞或是稍大的具有骨骼肌分化的肿瘤细胞均有不同程度的表达。MSA、desmin和myoglobin在小细胞肿瘤中染色的敏感性较低。

Purpose To investigate application of myogenic transcriptional regulatory proteins in diagnosis and differential diagnosis of small cell tumors. Methods Fifty six small cell tumors, including 19 embryonal and 6 alveolar rhabdomyosarcomas (RMS), 3 Wilm' tumor, 14 Ewing's sarcomas/PNETs, 14 neuroblastomas, and other 4 pleomorphic RMS were stained for MyoD1, myogenin, MSA, desmin, myoglobin and CD99 with immunohistochemical techniques. Results It was found that 21/29(72 41%) and 20/29(68 96%) rhabdomyosarcoma stained positively for MyoD1 and myogenin. Except for pleomorphic RMS, nuclear negative immunostaining for 4 MyoD1 and 5 myogenin were found no overlapping. Nuclear expression was positively in 2 for MyoD1 and in 1 for myogenin in Wilm' tumor of childhood, but both negatively in 1 Wilm tumor of adult. None of 14 neuroblastomas and 14 Ewing's sarcomas/PNETs was positive nuclear stained for MyoD1 and myogenin. However, it was found that the expression of MyoD1 and myogenin seemed to be inversely related to the differentiated degree of RMS, and these two proteins were expressed in higher fraction of small primitive cell and in lower fraction of larger myoblasts with skeletal muscle differentiation. The fraction of nuclear positive expression of MyoD1 was higher than that of myogenin in RMS; the expression of myogenin appeared to be prominent in small cells, however, either small primitive cells or larger myoblasts with skeletal muscle differentiation was somehow stained positively by MyoD1. The immunostaining sensitivity of MSA, desmin, and myoglobin in small tumor cells was lower. Conclusions For diagnosis and differential diagnosis of small cell rhabdomyosarcomas, the proteins of MyoD1 and myogenin are two higher sensitivity and specificity, and when suspect to embryonal and alveolar RMS, it helps to determine diagnosis that using a panel of antibodies comprising MyoD1, myogenin, MSA, desmin and myoglobin is recommended.