BIRC5 and hepatocellular carcinoma: The mTOR monotherapy using either everolimus or sirolimus effectively inhibited the downstream targets of the mTOR and survivin, resulting in tumor growth inhibition in 7 out of the 15 (46.7%) HCC PDX models (HCC05–0411B, HCC06–1009, HCC13–0212, HCC19–0509, HCC24–0309, HCC25–0705A, and HCC26–0808B).