MTOR and hepatocellular carcinoma: Comparative studies identified in our review suggest that sirolimus-based immunosuppression is associated with higher rates of survival after liver transplantation for HCC compared to an alternative immunosuppressant [15, 55, 65]; mTOR inhibitors thus show promise as the preferred immunosuppressive agent in patients transplanted for end-stage liver disease with HCC and further randomized trials are currently underway that should increase the evidence base for the use of mTOR inhibitors in this patient subset (NCT00355862, NCT01374750, and NCT00554125).