Here, we evaluated the therapeutic potential of two thiol isomerase inhibitors—isoquercetin (ISOQ), a selective PDI inhibitor, and zafirlukast (ZAF), a broad‐spectrum inhibitor of thiol isomerases such as PDI and ERp57—individually and in combination, in a xenograft model of ovarian cancer. This evidence concerns the gene PDIA3 and ovarian cancer.