EGFR and squamous cell carcinoma: Icariside II displays significant antitumor activity against A431 human epidermoid carcinoma cells in vitro and in mice bearing osteosarcoma sarcoma-180 in vivo by suppressing the phosphorylation of EGFR, down-regulating EGFR downstream signal PI3K/AKT and Raf/MEK/ERK as well as mTOR pathways in these cancer cells (Wu et al., 2013b; Geng et al., 2014).