Department of Tumor Biology, Center of Experimental Medicine, and Department of Gynecology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Clin Cancer Res. 2012 Feb 15;18(4):993-1003. doi: 10.1158/1078-0432.CCR-11-2100. Epub 2012 Jan 6.
Circulating tumor cells (CTC) might function as early markers for breast cancer metastasis or monitoring therapy efficacy. Enrichment and identification of CTCs are based on epithelial markers that might be modulated during epithelial-mesenchymal transition. Little is known about the expression of keratins in CTCs and whether all CTCs can be detected with antibodies directed against a limited panel of keratins.
Protein expression of keratin 2, 4-10, 13-16, 18, and 19 were assessed by a cocktail of antibodies (C11, AE1, AE3, and K7) and keratin antibodies C11 and A45-B/B3 alone in 11 breast cancer cell lines and 50 primary breast carcinomas and their lymph node metastases. Furthermore, CTCs were assessed in blood of 70 metastatic breast cancer patients.
Claudin-low cell lines did not show expression of normal breast epithelial keratins but were positive for K14 and K16, detected by the cocktail only. Primary breast carcinomas showed changes in keratin expression during metastatic progression to the lymph nodes. In 35 of 70 patients CTCs were identified, of which 83%, 40%, and 57% were identified by the cocktail, C11 and A45-B/B3, respectively. Identification of CTCs by the cocktail was associated with shorter survival (P < 0.01). In silico analyses revealed association between KRT16 expression and shorter relapse-free survival in metastatic breast cancer.
Breast cancer cells show a complex pattern of keratin expression with potential biologic relevance. Individual keratin antibodies recognizing only a limited set of keratins inherit the risk to miss biologically relevant CTCs in cancer patients, and antibody cocktails including these keratins are therefore recommended.
循环肿瘤细胞（CTC）可能作为乳腺癌转移的早期标志物或监测治疗效果。CTC 的富集和鉴定基于上皮标志物，这些标志物可能在上皮-间充质转化期间发生调节。关于 CTC 中角蛋白的表达以及是否可以使用针对有限角蛋白面板的抗体检测到所有 CTC 知之甚少。
通过角蛋白 2、4-10、13-16、18 和 19 的抗体鸡尾酒（C11、AE1、AE3 和 K7）以及单独的角蛋白抗体 C11 和 A45-B/B3 评估 11 种乳腺癌细胞系和 50 种原发性乳腺癌及其淋巴结转移的蛋白表达。此外，还评估了 70 名转移性乳腺癌患者的血液中的 CTC。
Claudin-low 细胞系不表达正常乳腺上皮角蛋白，但对鸡尾酒检测的 K14 和 K16 呈阳性。原发性乳腺癌在转移到淋巴结的过程中角蛋白表达发生变化。在 70 名患者中有 35 名患者检测到 CTC，其中 83%、40%和 57%分别通过鸡尾酒、C11 和 A45-B/B3 检测到。通过鸡尾酒鉴定 CTC 与较短的生存时间相关（P < 0.01）。在计算机分析中，发现 KRT16 表达与转移性乳腺癌无复发生存时间缩短之间存在关联。
乳腺癌细胞表现出具有潜在生物学相关性的复杂角蛋白表达模式。仅识别有限角蛋白集合的单个角蛋白抗体具有错过癌症患者中生物学上相关的 CTC 的风险，因此建议使用包括这些角蛋白的抗体鸡尾酒。
