EGFR and squamous cell carcinoma: Two 4′-methylthio-trans-stilbene derivatives possessing one (3-M-4′-MTS; S2) and two (3,5-DM-4′-MTS; S5) methoxy groups were assessed, and immortalized human HaCaT keratinocytes and human epidermoid carcinoma A431 cells differing in EGFR constitutive expression were applied as an experimental model.