SIRT1 and Hyperkeratosis: As expected, the knockdown of SIRT1 attenuated the differentiation of keratinocytes under CdMSORA or s-HBEGF recombinant protein treatment (Fig. 5b, c) without affecting the proliferation of HaCaT cells (Fig. 5d, e), suggesting that SIRT1 indeed contributed to keratinocyte differentiation in sorafenib-induced hyper-keratosis.