Objective: To investigate the expression of YEATS domain-containing protein 4 (YEATS4) in pancreatic cancer tissue and its clinical significance. 
Methods: Eighty surgical specimens of pancreatic cancer tissue and adjacent tissue confirmed by pathological examination were used to construct the tissue microarrays. The YEATS4 expressions in pancreatic cancer and adjacent tissues were detected by immunohistochemical staining. The relations of the YEATS4 expression in pancreatic cancer tissue with the clinicopathologic features and prognosis of pancreatic cancer patients were analyzed.
Results: The results of immunohistochemical staining results showed that the positive expression rate of YEATS4 in pancreatic cancer tissue was significantly higher than that in adjacent tissue (56.25% vs. 26.25%, P<0.05). The positive YEATS4 expression was significantly associated with sex (P=0.037), TMN stage (P<0.001), perineural invasion (P=0.006), lymphatic metastasis (P<0.001) and vascular metastasis (P=0.042) in patients with pancreatic cancer. In the entire group, the survival rate in patients with negative YEATS4 expression was significantly higher than that in those with positive YEATS4 expression (χ2=7.593, P=0.0059); subgroup analysis showed that the significant relationship between positive YEATS4 expression and unfavorable prognosis only was only seen in patients with TNM stage III/IV, lymphatic metastasis, perineural invasion, and vascular metastasis (all P<0.05). YEATS4 expression was an independent risk factor for the prognosis of pancreatic cancer patients (HR=2.1, 95% CI=1.1–4.2, P=0.026).
Conclusion: The YEATS4 expression in pancreatic cancer is significantly increased, which may be involved in the progression of pancreatic cancer, and it may be a potential prognostic marker and therapeutic target for pancreatic cancer.