Cells of the human breast gland express an array of keratins, of which some are used for characterizing both normal and neoplastic breast tissue. However, the expression pattern of certain keratins has yet to be detailed. Here, the expression of a differentiation marker of epidermal epithelium, keratin 10 (K10), was investigated in the human breast gland. While in normal breast tissue generally less than 1% of luminal epithelial cells expressed K10, in women >30 years of age glandular structures with K10-positive (K10^pos) cells were found at higher frequency than in younger women. K10^pos cells belong to a mature luminal compartment as they were negative for cKIT, positive for Ks20.8, and mostly non-cycling. In breast cancer, around 16% of primary breast carcinomas tested were positive for K10 by immunohistochemistry. Interestingly, K10^pos tumor cells generally exhibit features of differentiation similar to their normal counterparts. Although this suggests that K10 is a marker of tumor differentiation, data based on gene expression analysis imply that high levels of K10 dictate a worse outcome for breast cancer patients. These findings can form the basis of future studies that should unravel which role K10 may play as a marker of breast cancer:

人类乳腺细胞表达一系列角蛋白，其中一些用于表征正常和肿瘤乳腺组织。然而，某些角蛋白的表达模式尚未详细说明。在这里，表皮上皮的分化标志物角蛋白 10 (K10) 的表达在人乳腺中进行了研究。虽然在正常乳腺组织中，通常不到 1% 的管腔上皮细胞表达 K10，但在 30 岁以上的女性中，K10 阳性 (K10 ^pos ) 细胞的腺体结构表达频率高于年轻女性。K10 ^POS细胞属于成熟的腔室，因为它们对 cKIT 呈阴性，对 Ks20.8 呈阳性，并且大部分是非循环的。在乳腺癌中，大约 16% 的原发性乳腺癌通过免疫组织化学检测为 K10 阳性。有趣的是，K10 ^pos肿瘤细胞通常表现出与其正常对应物相似的分化特征。尽管这表明 K10 是肿瘤分化的标志物，但基于基因表达分析的数据表明，高水平的 K10 决定了乳腺癌患者的预后更差。这些发现可以构成未来研究的基础，这些研究应该阐明 K10 作为乳腺癌标志物可能发挥的作用：