Our study revealed that the poor prognosis of ovarian cancer (HR = 1.42, 95% CI: 1.02–1.72, p = 0.0312), pancreatic ductal adenocarcinoma (HR = 1.55, 95% CI: 1.02–2.36, p = 0.039), thymoma (HR = 4.58, 95% CI: 0.93–22.53, p = 0.041), and bladder cancer (HR = 1.36, 95% CI: 1.01–1.83, p = 0.04) was related to the high expression of MUC4. Furthermore, the increased expression of MUC4 was related with prolonged overall survival in kidney renal clear cell carcinoma (HR = 0.67, 95% CI: 0.5–0.91, p = 0.0099). The gene discussed is MUC4; the disease is pancreatic ductal adenocarcinoma.