NFKB1 and Dubin-Johnson syndrome: However, investigating other transporters such as the MRP2, a transporter mutated in patients with Dubin-Johnson syndrome [1, 3, 5, 6], or the Farnesoid X receptor, a transporter triggering hepatic inflammation via the NF-κB pathway [25], would be helpful in future studies on a larger population of PSC patients to further elucidate the disease mechanisms of cholestasis development due to altered expression of transporters in hepatocytes of patients with chronic cholestatic liver diseases as PSC.