P4HB and glioblastoma: A recent study demonstrated that specific toxoflavin analogs can suppress the overexpression of protein disulfide isomerase (PDI) in glioblastoma and induce the Nrf2 antioxidant response, endoplasmic reticulum (ER) stress response, and autophagy while also acting as novel chemical probes to inhibit PDI as a therapeutic target for brain cancer25.