MUS81 and hepatocellular carcinoma: In addition, the TUNEL results in xenograft tumors showed that the apoptosis rate in tumors generated from HepG2shMus81 cells was significantly higher than those came from HepG2shCtrl cells (Fig. 7E and F), having provided the in vivo proofs for the elevated apoptosis induced by EPI in Mus81 depleted HCC cells.