Heterogeneous Expression of Claudin-4 in Human Colorectal Cancer: Decreased Claudin-4 Expression at the Invasive Front Correlates Cancer Invasion and Metastasis

<i>Objective:</i> Claudin-4 plays a key role in constructing the tight junction (TJ), and altered claudin-4 expression has been documented in various human malignancies; however, little is known about the biological significance of claudin-4 in colorectal cancers (CRCs). The aim of this study is to investigate the significance of claudin-4 expression in CRC and its association with clinicopathological factors....