EGFR and squamous cell carcinoma: A report also shows that shikonin significantly suppresses the growth of human epidermoid carcinoma cells (A431 cells) in concentration- and time-dependent manner and decreased the phosphorylation of EGFR and extracellular signal-regulated kinase (ERK)1/2, whereas increasing the phosphorylation of c-Jun N-terminal kinase (JNK)1/2 [20].