Further, inhibitory effect of honokiol on EGFR in tumor xenografts was also associated with reduced expressions of mTOR and its down-stream target proteins p70S6K and 4E-BP1, suggesting the involvement of these molecular targets in preventing the in vivo growth of HNSCC xenografts by honokiol in mice (Figure 6D). Here, EGFR is linked to head and neck squamous cell carcinoma.