A huge array of function is played by the Wnt/β-catenin signaling pathway in development by balancing gene expression through the modulation of cell-specific DNA binding downstream effectors such as T-cell factor/lymphoid enhancer factor (TCF/LEF). The β-catenin/TCF-4 complex is a central regulatory switch for differentiation and proliferation of intestinal cells (both normal and malignant). Thus, in the present study we evaluated each of 60 cases of sporadic adenocarcinoma, alongside adjoining and normal mucosa specimens of colorectum in humans, for mutation and expression analysis of the gene coding for TCF-4 protein. DNA sequencing following PCR amplification and SSCP analysis (single strand conformation polymorphism) was employed to detect TCF-4 gene mutations in the case of exon 1. Quantitative real-time (qRT) PCR, immunohistochemistry (IHC), confocal microscopy and western blot analysis were used to detect TCF-4 gene/protein expression. Sequencing analysis confirmed 5/60 patients with a point mutation in exon 1 of the TCF-4 gene in tumor samples. mRNA expression using qRT-PCR showed approximately 83% decreased TCF-4 mRNA expression in tumor tissue and adjoining mucosa compared to normal mucosa. Similarly, a significant decrease in protein expression using IHC showed decreased TCF-4 protein expression in tumor tissue and adjoining mucosa compared to normal mucosa, which also corresponds to some important clinicopathological factors, including disease metastasis and tumor grade. Mutational alterations and downregulation of TCF-4 mRNA and hence decreased expression of TCF-4 protein in tumors suggest its involvement in the pathogenesis of CRC. A remarkable decrease in TCF-4 mRNA and protein expression was detected in tumorous and adjoining tissues compared to normal mucosa. Hence the alterations in genomic architecture along with downregulation of TCF-4 mRNA and decreased expression of TCF-4 protein in tumors, which is in accordance with clinical features, suggest its involvement in the pathogenesis of CRC. Thus, deregulation and collaboration of TCF-4 with CRC could be a concrete and distinctive feature in the prognosis of the disease at an early stage of development.

中文翻译：

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TCF 4肿瘤抑制因子：人类散发性结直肠癌预后的分子靶点。

Wnt/β-连环蛋白信号通路在发育过程中通过调节细胞特异性 DNA 结合下游效应子（如 T 细胞因子/淋巴增强因子 (TCF/LEF)）来平衡基因表达，从而发挥了巨大的一系列功能。β-连环蛋白/TCF-4 复合物是肠细胞（正常和恶性）分化和增殖的中心调节开关。因此，在本研究中，我们评估了 60 例散发性腺癌中的每一个，以及人类结肠直肠的相邻和正常粘膜标本，以对编码 TCF-4 蛋白的基因进行突变和表达分析。在外显子 1 的情况下，采用 PCR 扩增和 SSCP 分析（单链构象多态性）后的 DNA 测序来检测 TCF-4 基因突变。定量实时 (qRT) PCR、免疫组织化学 (IHC)、共聚焦显微镜和蛋白质印迹分析用于检测 TCF-4 基因/蛋白质表达。测序分析证实，5/60 名患者在肿瘤样本中 TCF-4 基因外显子 1 存在点突变。与正常黏膜相比，使用 qRT-PCR 的 mRNA 表达显示肿瘤组织和邻近黏膜中 TCF-4 mRNA 表达降低约 83%。同样，使用 IHC 显着降低蛋白质表达表明，与正常黏膜相比，肿瘤组织和邻近黏膜中 TCF-4 蛋白表达降低，这也对应于一些重要的临床病理因素，包括疾病转移和肿瘤分级。TCF-4 mRNA 的突变改变和下调以及肿瘤中 TCF-4 蛋白的表达降低表明其参与了 CRC 的发病机制。与正常黏膜相比，在肿瘤组织和毗邻组织中检测到 TCF-4 mRNA 和蛋白质表达显着降低。因此，基因组结构的改变以及肿瘤中 TCF-4 mRNA 的下调和 TCF-4 蛋白在肿瘤中的表达降低，这与临床特征一致，表明其参与了 CRC 的发病机制。因此，TCF-4 与 CRC 的放松管制和协作可能是疾病早期发展阶段预后的一个具体而独特的特征。提示其参与 CRC 的发病机制。因此，TCF-4 与 CRC 的放松管制和协作可能是疾病早期发展阶段预后的一个具体而独特的特征。提示其参与 CRC 的发病机制。因此，TCF-4 与 CRC 的放松管制和协作可能是疾病早期发展阶段预后的一个具体而独特的特征。