CircPVT1 sponge miR-30a-5p targets and binds frizzled class receptor 3 (FZD3), affects the expression levels of p-β-catenin, GPX4 and SLC7A11, inhibits cellular ferroptosis, affects esophageal cancer 5-FU chemotherapy sensitivity and promotes the development of esophageal cancer. The gene discussed is GPX4; the disease is esophageal cancer.