Nayar R, Breland C, Bedrossian U, Masood S, DeFrias D, Bedrossian C W
Department of Pathology, Northwestern University, Chicago, IL, USA.
Ann Diagn Pathol. 1999 Jun;3(3):165-73. doi: 10.1016/s1092-9134(99)80044-6.
The identification of an intact layer of myoepithelial cells (MECs) located between epithelial cells and the basal lamina is useful in differentiating benign breast lesions and carcinoma in situ from invasive breast carcinoma. In the present study we used three antibodies considered to be putative markers of MECs (S100 protein, muscle-specific actin [HHF-35], and smooth muscle actin [SMA]) in 100 formalin-fixed, paraffin-embedded histologic sections of breast in an attempt to compare their value in demonstrating MECs in benign breast tissue and breast carcinomas. We concluded that for identifying MECs in benign breast tissue, SMA appears to be the most reliable, followed closely by HHF-35, but S100 is very unreliable for this purpose. In breast carcinoma, all three stains showed variable cross-reactivity with myofibroblasts, being greatest with SMA. A significant number of tumor cells in ductal carcinoma, both intraductal and invasive, stain with these markers and this "cross-reactivity" is extremely high with HHF-35. Thus, immunohistochemistry should be interpreted cautiously in differentiating benign, in situ, and invasive breast neoplasms. The "cross-reactivity" also suggests the possibility of myoepithelial differentiation and/or high actin content of breast tumor cells.
鉴定位于上皮细胞和基膜之间完整的肌上皮细胞（MECs）层，有助于鉴别乳腺良性病变、原位癌与浸润性乳腺癌。在本研究中，我们在100例经福尔马林固定、石蜡包埋的乳腺组织学切片中使用了三种被认为是MECs假定标志物的抗体（S100蛋白、肌肉特异性肌动蛋白[HHF-35]和平滑肌肌动蛋白[SMA]），试图比较它们在显示乳腺良性组织和乳腺癌中MECs方面的价值。我们得出结论，对于识别乳腺良性组织中的MECs，SMA似乎是最可靠的，其次是HHF-35，但S100在这方面非常不可靠。在乳腺癌中，所有三种染色与肌成纤维细胞均表现出不同程度的交叉反应，其中SMA的交叉反应最强。导管内癌和浸润性导管癌中的大量肿瘤细胞均被这些标志物染色，且与HHF-35的这种“交叉反应”极高。因此，在鉴别乳腺良性、原位和浸润性肿瘤时，免疫组化结果应谨慎解读。这种“交叉反应”还提示乳腺肿瘤细胞存在肌上皮分化和/或高肌动蛋白含量的可能性。
