In esophageal squamous cell cancer (ESCC), PX-478 promotes apoptosis, induces cell cycle arrest in the G2/M phase, represses the epithelial–mesenchymal transition (EMT), and reduces cyclooxygenase-2 (COX-2) and PD-L1 expression in ESCC cells [352]; it also enhances radiosensitivity in prostate carcinoma cells under both normoxic and hypoxic conditions, arrests the cell cycle in S/G2M, and phosphorylates the histone H2AX, inducing double-strand breaks (DSB) in DNA [353]. This evidence concerns the gene PTGS2 and esophageal squamous cell carcinoma.