Departments of Pathology, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA.
Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
Mod Pathol. 2014 Apr;27(4):496-501. doi: 10.1038/modpathol.2013.161. Epub 2013 Sep 27.
Epithelioid sarcoma is a rare, aggressive keratin-positive sarcoma that co-expresses CD34 in 50% of cases and may mimic an angiosarcoma. Recently, we have observed one case of epithelioid sarcoma that labeled for ERG, an ETS family regulatory transcription factor, which is considered to be a reliable marker for vascular differentiation. We investigated the prevalence of nuclear expression of ERG and FLI1, a homologous transcription factor, in these tumors. A formalin-fixed paraffin-embedded tissue microarray of 37 epithelioid sarcomas was examined. Immunohistochemistry was performed using anti-ERG monoclonal antibody to the N-terminus, anti-ERG monoclonal antibody to the C-terminus and anti-FLI1 monoclonal antibody. Comparison was made with CD34, CD31, and D2-40 labeling. The extent of immunoreactivity was graded according to the percentage of positive tumor cell nuclei (0: no staining; 1+: <5%; 2+: 5-25%; 3+: 26-50%; 4+: 51-75%; and 5+: 76-100%), and the intensity of staining was graded as weak, moderate, or strong. Nuclear staining for the N-terminus of ERG was seen in 19 out of 28 cases: 10 with diffuse(4 to 5+) strong/moderate labeling; 1 with 2+ moderate labeling and 8 with weak labeling (1 to 4+, 2 each). Focal staining for the C-terminus of ERG was seen in only 1 out of 29 cases (2+ moderate). FLI1 labeling was seen in nearly all (28 out of 30) cases: 16 with diffuse (5+) predominantly moderate labeling, and 8 cases with diffuse(5+) weak labeling. The remainder had variable moderate (1 to 3+) or weak (1 to 4+) FLI1 staining. CD34 was positive in 22 out of 30 cases and D2-40 was found to be positive in 22 out of 31 cases. All cases were negative for CD31 (0 out of 30). Epithelioid sarcoma can label with antibodies to the N-terminus of ERG, FLI1, and D2-40, which may cause diagnostic confusion for a vascular tumor. A panel of other antibodies including SMARCB1 and CD31 should be used in evaluating these tumors. ERG antibody selection is also critical, as those directed against the C-terminus are less likely to label epithelioid sarcoma.
上皮样肉瘤是一种罕见的、侵袭性的、角蛋白阳性的肉瘤，在 50%的病例中共同表达 CD34，并且可能模仿血管肉瘤。最近，我们观察到一例上皮样肉瘤表达 ERG，一种 ETS 家族调节转录因子，被认为是血管分化的可靠标志物。我们研究了这些肿瘤中核表达 ERG 和 FLI1（一种同源转录因子）的普遍性。使用针对 ERG N 末端的单克隆抗体、针对 ERG C 末端的单克隆抗体和针对 FLI1 的单克隆抗体对 37 例上皮样肉瘤的福尔马林固定石蜡包埋组织微阵列进行了免疫组织化学检查。与 CD34、CD31 和 D2-40 标记进行了比较。根据阳性肿瘤细胞核的百分比（0：无染色；1+：<5%；2+：5-25%；3+：26-50%；4+：51-75%；和 5+：76-100%）对免疫反应性程度进行分级，并根据染色强度分为弱、中或强。在 28 例中的 19 例中观察到 ERG N 末端的核染色：10 例弥漫性（4 到 5+）强/中度标记；1 例 2+中度标记和 8 例弱标记（1 到 4+，各 2 例）。在 29 例中的 1 例中观察到 ERG C 末端的局灶性染色（2+中度）。在近 30 例中的 28 例中观察到 FLI1 标记：16 例弥漫性（5+）主要为中度标记，8 例弥漫性（5+）弱标记。其余的有不同程度的中度（1 到 3+）或弱（1 到 4+）FLI1 染色。在 30 例中的 22 例中 CD34 阳性，在 31 例中的 22 例中 D2-40 阳性。所有病例 CD31 均为阴性（0 例）。上皮样肉瘤可标记 ERG、FLI1 和 D2-40 的 N 末端抗体，这可能导致血管肿瘤的诊断混淆。应使用包括 SMARCB1 和 CD31 在内的其他抗体组合来评估这些肿瘤。选择 ERG 抗体也很关键，因为针对 C 末端的抗体不太可能标记上皮样肉瘤。
