Department of Pathology and Oncology, The Johns Hopkins University School of Medicine, 401N Broadway St Weinberg Bldg 2242, Baltimore, MD, 21231, USA.
Mod Pathol. 2021 Jan;34(Suppl 1):62-77. doi: 10.1038/s41379-020-00697-3. Epub 2020 Oct 27.
Immunohistochemistry is an essential component of diagnostic breast pathology. The emergence of novel assays and applications is accompanied by new interpretation criteria and potential pitfalls. Immunohistochemistry assists in supporting breast origin for primary or metastatic carcinomas and identifying non-mammary metastases to the breast; however, no single immunostain is perfectly sensitive nor specific. GATA3 and Sox10 are particularly useful immunostains to identify triple negative breast carcinoma, which are often negative for other markers of mammary differentiation. Sox10 labeling is a major potential diagnostic pitfall, as Sox10 and S-100 label both triple negative breast carcinoma and metastatic melanoma; a pan-cytokeratin immunostain should always be included for this differential diagnosis. Novel immunohistochemistry serves as surrogates for the molecular alterations unique to several of special-type breast carcinomas, including the use of MYB in adenoid cystic carcinoma, pan-TRK in secretory carcinoma, and mutant IDH2 in tall cell carcinoma with reversed polarity (TCCRP). In addition, PD-L1 immunohistochemistry is an emerging, albeit imperfect, biomarker for breast cancer immunotherapy, with different assay parameters and scoring criteria in breast carcinoma compared to other tumor types. The expanding repertoire of novel immunohistochemistry provides additional diagnostic tools and biomarkers that improve diagnostic breast pathology and patient care.
免疫组织化学是诊断性乳腺病理学的重要组成部分。新的检测方法和应用的出现伴随着新的解释标准和潜在的陷阱。免疫组织化学有助于支持原发性或转移性癌的乳腺起源，并识别非乳腺转移至乳房；然而，没有一种免疫染色是完全敏感或特异的。GATA3 和 Sox10 是特别有用的免疫染色，可用于识别三阴性乳腺癌，其通常对其他乳腺分化标志物呈阴性。Sox10 标记是一个主要的潜在诊断陷阱，因为 Sox10 和 S-100 标记三阴性乳腺癌和转移性黑色素瘤；这种鉴别诊断总是应该包括一个泛细胞角蛋白免疫染色。新型免疫组织化学可作为几种特殊类型乳腺癌特有的分子改变的替代物，包括在腺样囊性癌中使用 MYB、在分泌癌中使用 pan-TRK，以及在极性反转的高细胞癌（TCCRP）中使用突变 IDH2。此外，PD-L1 免疫组织化学是一种新兴的、尽管不完美的乳腺癌免疫治疗生物标志物，与其他肿瘤类型相比，在乳腺癌中具有不同的检测参数和评分标准。新型免疫组织化学的扩展谱提供了额外的诊断工具和生物标志物，可改善诊断性乳腺病理学和患者护理。
