Section of Oncopathology and Regenerative Biology, Department of Pathology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
Liver Int. 2011 Jan;31(1):120-31. doi: 10.1111/j.1478-3231.2010.02359.x. Epub 2010 Oct 21.
GC33 is a recently developed monoclonal antibody against human glypican-3 (GPC3), which is significantly upregulated in hepatocellular carcinoma (HCC). GC33 recognizes a GPC3 ectodomain and shows significant antitumour activity in vivo. Thus, humanized GC33 antibody may be a promising tool for treating HCC having cell surface GPC3 expression.
This study aims to determine the specificity, subcellular localization and prognostic impact of GPC3 immunoreactivity detected by GC33 in HCC clinical specimens.
Immunohistochemical analysis was performed for 194 cases of resected HCC and prognostic analysis was performed for 185 eligible cases. Two antigen retrieval methods (autoclave and protease pretreatments) were used for immunohistochemistry and compared. The immunoscore system reflecting circumferential membranous GPC3 immunoreactivity was developed using either the autoclave or protease methods. The GPC3 mRNA level was analysed by quantitative real-time reverse transcription-polymerase chain reaction.
GC33 immunostaining after autoclave is a sensitive method and revealed the GPC3 expression (≥20% of tumour cells) in the majority (77%) of HCC samples tested. Alternatively, protease pretreatment showed lower sensitivity, but was superior for evaluating the intensity and subcellular localization of GPC3. Correlation between immunoscores and the GPC3 mRNA level was also confirmed. Subsequent clinicopathological analysis revealed worse prognoses in HCC patients with circumferential membranous GPC3 immunoreactivity. For HCC patients with hepatitis C virus (HCV) infection in particular, the high membranous GPC3 immunoreactivity was an independent prognostic factor for disease-free survival.
Circumferential membranous GPC3 immunoreactivity in HCC indicates poorer prognosis particularly in patients with HCV infection.
GC33 是一种新开发的针对人磷脂酰聚糖-3（GPC3）的单克隆抗体，GPC3 在肝细胞癌（HCC）中显著上调。GC33 识别 GPC3 的外显子结构域，在体内具有显著的抗肿瘤活性。因此，人源化 GC33 抗体可能是治疗具有细胞表面 GPC3 表达的 HCC 的有前途的工具。
本研究旨在确定 GC33 在 HCC 临床标本中检测到的 GPC3 免疫反应的特异性、亚细胞定位和预后影响。
对 194 例 HCC 切除标本进行免疫组织化学分析，并对 185 例合格病例进行预后分析。使用两种抗原修复方法（高压蒸汽和蛋白酶预处理）进行免疫组织化学，并进行比较。使用高压蒸汽或蛋白酶方法开发了反映 GPC3 免疫反应的环形膜免疫评分系统。通过实时定量逆转录-聚合酶链反应分析 GPC3 mRNA 水平。
高压蒸汽后的 GC33 免疫染色是一种敏感的方法，揭示了大多数（77%）测试的 HCC 样本中的 GPC3 表达（≥20%的肿瘤细胞）。另一方面，蛋白酶预处理的敏感性较低，但对于评估 GPC3 的强度和亚细胞定位更有优势。免疫评分与 GPC3 mRNA 水平之间的相关性也得到了证实。随后的临床病理分析显示，具有环形膜 GPC3 免疫反应的 HCC 患者预后较差。特别是对于 HCV 感染的 HCC 患者，高膜 GPC3 免疫反应是无病生存的独立预后因素。
HCC 中的环形膜 GPC3 免疫反应表明预后较差，特别是在 HCV 感染患者中。
