University of Nice-Sophia Antipolis, France.
Clin Cancer Res. 2012 Mar 1;18(5):1313-22. doi: 10.1158/1078-0432.CCR-11-2339. Epub 2012 Jan 6.
Epidermal growth factor receptor (EGFR) overexpression is associated with poor prognosis in head and neck squamous cell carcinoma (HNSCC). Despite intensive biomarker studies, a consensual method for assessing EGFR protein expression is still lacking. Here we set out to compare three EGFR detection methods in tumor specimens from HNSCC patients.
Tumors were prospectively excised from a series of 79 high-risk HNSCC patients enrolled in a GORTEC-sponsored clinical trial. EGFR expression was determined using a ligand-binding assay on membranes, Western blotting (WB) on membranes and total homogenates, and immunohistochemistry (IHC) on tissue microarrays. In addition, phosphorylated EGFR (pEGFR) was measured by WB on membranes.
Distributions and ranges of tumor EGFR expression were method dependent. Moderate positive correlations (Spearman coefficient r ≈ 0.50) were observed between EGFR expression measured by the binding assay and WB or IHC. pEGFR levels positively and significantly correlated with total EGFR expression measured by WB or ligand binding, but not by IHC. The highest correlation (r = 0.85) was observed between EGFR and pEGFR levels, both measured by WB on membranes. Interestingly, the fraction of phosphorylated receptor (pEGFR/EGFR both measured by WB on membranes) significantly declined with increasing tumor EGFR expression, by all assessment methods used.
This study shows significant correlations between EGFR detection methods. The observed relationships between EGFR and pEGFR indicate that high-throughput pEGFR/EGFR analyses merit further investigations and consideration for routine use in patient samples.
表皮生长因子受体（EGFR）过表达与头颈部鳞状细胞癌（HNSCC）的预后不良相关。尽管进行了大量的生物标志物研究，但仍缺乏评估 EGFR 蛋白表达的共识方法。在这里，我们旨在比较三种 EGFR 检测方法在 HNSCC 患者肿瘤标本中的应用。
前瞻性切除了 79 名高风险 HNSCC 患者的肿瘤组织，这些患者参加了 GORTEC 赞助的一项临床试验。使用膜上的配体结合测定法、膜和总匀浆上的 Western blot（WB）以及组织微阵列上的免疫组织化学（IHC）来确定 EGFR 表达。此外，还通过膜上的 WB 测量磷酸化 EGFR（pEGFR）。
肿瘤 EGFR 表达的分布和范围取决于检测方法。在配体结合测定法和 WB 或 IHC 测量的 EGFR 表达之间观察到中等程度的正相关（Spearman 系数 r ≈ 0.50）。pEGFR 水平与 WB 或配体结合测量的总 EGFR 表达呈正相关且显著相关，但与 IHC 不相关。在膜上的 WB 测量的 EGFR 和 pEGFR 水平之间观察到最高的相关性（r = 0.85）。有趣的是，通过膜上的 WB 测量的磷酸化受体的比例（pEGFR/EGFR）均随着肿瘤 EGFR 表达的增加而显著下降，所有评估方法均如此。
本研究显示 EGFR 检测方法之间存在显著相关性。观察到的 EGFR 和 pEGFR 之间的关系表明，高通量的 pEGFR/EGFR 分析值得进一步研究，并考虑在患者样本中常规使用。
