PCNA and neoplasm: It has been reported that EMT is closely related to tumor invasion and metastasis, and CAF can accelerate disease progression by inducing EMT in tumor cells.[23] In the in vitro co‐culture models with U‐CH1 or UM‐Chor1 cells, we found that hypoxia‐treated CAF could induce the expression of EMT related proteins (including PCNA, TGF‐B1, N‐cadherin, and MMP‐2) on tumor cells, while reducing the expression abundance of E‐cadherin (Figure 2F; Figure S2F, Supporting Information).