E‐cadherin, an important suppressor of tumor invasion, can be controlled by tumor cells.[167, 168, 169] To elucidate the role of E‐cadherin in tumor tissues, one study presented a tumor invasion model by embedding epidermoid carcinoma A431 cells (shown in red) into a collagen gel in vitro (Figure 9a).[170] The researchers found that overexpressed E‐cadherin (depicted in green) in tumor cells can impede cell motility, suggesting that tumor cells depend on E‐cadherin‐mediated cell‐cell adhesion during the movement process in vivo. The gene discussed is CDH1; the disease is squamous cell carcinoma.