Cytokeratin 10 (CK10) is a type I acidic low molecular weight cytokeratin which is mainly expressed in keratinizing squamous epithelium of the skin. Variable levels of CK10 protein have been described in squamous carcinomas of different sites and in some other epithelial neoplasms. To comprehensively determine the prevalence of CK10 expression in normal and neoplastic tissues, a tissue microarray containing 11,021 samples from 131 different tumor types and subtypes was analyzed by immunohistochemistry. CK10 immunostaining was detectable in 41 (31.3 %) of 131 tumor categories, including 18 (13.7 %) tumor types with at least one strongly positive case. The highest rate of positive staining was found in squamous cell carcinomas from various sites of origin (positive in 18.6 %–66.1 %) and in Warthin tumors of salivary glands (47.8 %), followed by various tumor entities known to potentially exhibit areas with squamous cell differentiation such as teratomas (33.3 %), basal cell carcinomas of the skin (14.3 %), adenosquamous carcinomas of the cervix (11.1 %), and several categories of urothelial neoplasms (3.1 %–16.8 %). In a combined analysis of 956 squamous cell carcinomas from 11 different sites of origin, reduced CK10 staining was linked to high grade (p < 0.0001) and advanced stage (p = 0.0015) but unrelated to HPV infection. However, CK10 staining was not statistically related to grade (p = 0.1509) and recurrence-free (p = 0.5247) or overall survival (p = 0.5082) in 176 cervical squamous cell carcinomas. In the urinary bladder, CK10 staining occurred more commonly in muscle-invasive (17.7 %) than in non-invasive urothelial carcinomas (4.0 %–6.0 %; p < 0.0001). In summary, our data corroborate a role of CK10 as a suitable marker for mature, keratinizing squamous cell differentiation in epithelial tissues. CK10 immunohistochemistry may thus be instrumental for a more objective evaluation of the clinical significance of focal squamous differentiation in cancer.

细胞角蛋白 10 (CK10) 是一种 I 型酸性低分子量细胞角蛋白，主要在皮肤的角化鳞状上皮中表达。已在不同部位的鳞状细胞癌和一些其他上皮肿瘤中描述了不同水平的 CK10 蛋白。为了全面确定正常和肿瘤组织中 CK10 表达的普遍性，通过免疫组织化学分析了包含来自 131 种不同肿瘤类型和亚型的 11,021 个样本的组织微阵列。CK10 免疫染色在 131 种肿瘤类别中的 41 种 (31.3%) 中可检测到，其中包括至少 1 例强阳性病例的 18 种 (13.7%) 肿瘤类型。在来自不同起源部位的鳞状细胞癌（阳性率为 18.6 %–66.1 %）和唾液腺的 Warthin 肿瘤（47.8 %）中发现阳性染色率最高，其次是已知可能表现出鳞状细胞分化区域的各种肿瘤实体，例如畸胎瘤（33.3%）、皮肤基底细胞癌（14.3%）、宫颈腺鳞癌（11.1%）和几类尿路上皮肿瘤（ 3.1 %–16.8 %）。在对来自 11 个不同起源部位的 956 例鳞状细胞癌的综合分析中，CK10 染色减少与高级别 (p < 0.0001) 和晚期 (p = 0.0015) 相关，但与 HPV 感染无关。然而，CK10 染色与 176 例宫颈鳞状细胞癌的分级 (p = 0.1509) 和无复发 (p = 0.5247) 或总生存期 (p = 0.5082) 没有统计学意义。在膀胱中，CK10 染色在肌肉浸润性（17.7%）中比在非浸润性尿路上皮癌中更常见（4.0%–6.0%；p < 0.0001）。总之，我们的数据证实了 CK10 作为上皮组织中成熟、角化鳞状细胞分化的合适标记物的作用。因此，CK10 免疫组织化学可能有助于更客观地评估癌症局灶性鳞状细胞分化的临床意义。