IL6 and hepatocellular carcinoma: In addition to the effect of ID1/p16/IL6 axis on sorafenib efficacy, we observed that sorafenib administration in HCC cells induced senescence through dose-dependently inhibiting ID1 expression but stimulating p16 and IL6 (Fig. 7a–c), accompanied with the enhancement of SA-β-gal activity (Fig. 7d).