Chen F F, Yan J J, Chang K C, Lai W W, Chen R M, Jin Y T
Department of Pathology, National Cheng Kung University Medical Centre, Tainan, Taiwan.
Histopathology. 1996 Dec;29(6):541-7. doi: 10.1046/j.1365-2559.1996.d01-540.x.
Mcl-1 protein is a new member of the bcl-2 protein family. It is believed to be a blocker of apoptosis but might be different from bcl-2 in the control of apoptosis. Using immunostaining of formalin-fixed, paraffin-embedded sections, we investigated the expression of Mcl-1 in 42 thymic epithelial tumours: three medullary thymomas, five mixed thymomas, seven cortical thymomas, eight well-differentiated thymic carcinomas, 14 squamous cell carcinomas, four lymphoepithelioma-like carcinomas and one undifferentiated carcinoma, bcl-2 immunocytochemical localization was also performed for comparison. High-grade thymic carcinomas, especially squamous cell carcinomas, revealed more intense Mcl-1 immunoreactivity as compared to other subtypes (P < 0.001). In cases that co-expressed Mcl-1 and bcl-2, the less differentiated cells had more intense expression of bcl-2, while the more differentiated cells displayed stronger Mcl-1 immunoreactivity. The differential expression of Mcl-1 and bcl-2 in neoplastic cells provides evidence that these proteins may play different roles in the processes of programmed cell death in thymic neoplasms. The finding that thymic carcinomas have stronger immunoreactivity for Mcl-1 indicates that this protein could be a useful marker to differentiate aggressive thymic epithelial tumours from indolent ones.
Mcl-1蛋白是bcl-2蛋白家族的新成员。它被认为是一种细胞凋亡阻滞剂，但在细胞凋亡控制方面可能与bcl-2不同。我们通过对福尔马林固定、石蜡包埋切片进行免疫染色，研究了42例胸腺上皮肿瘤中Mcl-1的表达情况，这些肿瘤包括3例髓质型胸腺瘤、5例混合型胸腺瘤、7例皮质型胸腺瘤、8例高分化胸腺癌、14例鳞状细胞癌、4例淋巴上皮瘤样癌和1例未分化癌。同时进行bcl-2免疫细胞化学定位以作比较。与其他亚型相比，高级别胸腺癌，尤其是鳞状细胞癌，显示出更强的Mcl-1免疫反应性（P < 0.001）。在同时表达Mcl-1和bcl-2的病例中，分化程度较低的细胞bcl-2表达更强，而分化程度较高的细胞Mcl-1免疫反应性更强。肿瘤细胞中Mcl-1和bcl-2的差异表达表明，这些蛋白在胸腺肿瘤程序性细胞死亡过程中可能发挥不同作用。胸腺癌对Mcl-1具有更强免疫反应性这一发现表明，该蛋白可能是区分侵袭性胸腺上皮肿瘤与惰性肿瘤的有用标志物。
