Molecular Oncology Group, Institute of Pathology, Medical Faculty, RWTH Aachen University, Aachen, Germany.
BMC Cancer. 2009 Nov 24;9:410. doi: 10.1186/1471-2407-9-410.
Y-box binding protein-1 (YB-1) is the prototypic member of the cold shock protein family that fulfills numerous cellular functions. In the nucleus YB-1 protein orchestrates transcription of proliferation-related genes, whereas in the cytoplasm it associates with mRNA and directs translation. In human tumor entities, such as breast, lung and prostate cancer, cellular YB-1 expression indicates poor clinical outcome, suggesting that YB-1 is an attractive marker to predict patients' prognosis and, potentially, is suitable to individualize treatment protocols. Given these predictive qualities of YB-1 detection we sought to establish a highly specific monoclonal antibody (Mab) for diagnostic testing and its characterization towards outcome prediction (relapse-free and overall survival).
Hybridoma cell generation was carried out with recombinant YB-1 protein as immunogen and Mab characterization was performed using immunoblotting and ELISA with recombinant and tagged YB-1 proteins, as well as immunohistochemistry of healthy and breast cancer specimens. Breast tumor tissue array staining results were analyzed for correlations with receptor expression and outcome parameters.
YB-1-specific Mab F-E2G5 associates with conformational binding epitopes mapping to two domains within the N-terminal half of the protein and detects nuclear YB-1 protein by immunohistochemistry in paraffin-embedded breast cancer tissues. Prognostic evaluation of Mab F-E2G5 was performed by immunohistochemistry of a human breast cancer tissue microarray comprising 179 invasive breast cancers, 8 ductal carcinoma in situ and 37 normal breast tissue samples. Nuclear YB-1 detection in human breast cancer cells was associated with poor overall survival (p = 0.0046). We observed a close correlation between nuclear YB-1 detection and absence of progesterone receptor expression (p = 0.002), indicating that nuclear YB-1 detection marks a specific subgroup of breast cancer. Likely due to limitation of sample size Cox regression models failed to demonstrate significance for nuclear YB-1 detection as independent prognostic marker.
Monoclonal YB-1 antibody F-E2G5 should be of great value for prospective studies to validate YB-1 as a novel biomarker suitable to optimize breast cancer treatment.
Y 盒结合蛋白-1（YB-1）是冷休克蛋白家族的典型成员，具有多种细胞功能。在细胞核中，YB-1 蛋白协调增殖相关基因的转录，而在细胞质中，它与 mRNA 结合并指导翻译。在人类肿瘤实体中，如乳腺癌、肺癌和前列腺癌，细胞 YB-1 的表达表明临床预后不良，这表明 YB-1 是预测患者预后的有吸引力的标志物，并可能适合个体化治疗方案。鉴于 YB-1 检测的这些预测性质，我们试图建立一种高度特异性的单克隆抗体（Mab）用于诊断检测，并对其进行特征分析以预测预后（无复发生存和总生存）。
使用重组 YB-1 蛋白作为免疫原进行杂交瘤细胞生成，并使用免疫印迹和 ELISA 以及重组和标记的 YB-1 蛋白对 Mab 进行表征，以及对健康和乳腺癌标本进行免疫组织化学分析。分析乳腺癌组织阵列染色结果与受体表达和预后参数的相关性。
YB-1 特异性 Mab F-E2G5 与映射到蛋白 N 端一半两个结构域的构象结合表位结合，并通过免疫组织化学在石蜡包埋的乳腺癌组织中检测到核 YB-1 蛋白。通过对包含 179 例浸润性乳腺癌、8 例导管原位癌和 37 例正常乳腺组织样本的人类乳腺癌组织微阵列进行免疫组织化学分析，对 Mab F-E2G5 进行了预后评估。在人类乳腺癌细胞中检测到核 YB-1 与总生存不良相关（p = 0.0046）。我们观察到核 YB-1 检测与孕激素受体表达缺失之间存在密切相关性（p = 0.002），表明核 YB-1 检测标志着乳腺癌的一个特定亚群。由于样本量有限，Cox 回归模型未能证明核 YB-1 检测作为独立预后标志物的显著性。
单克隆 YB-1 抗体 F-E2G5 对于验证 YB-1 作为适合优化乳腺癌治疗的新型生物标志物的前瞻性研究将具有重要价值。
