Oral cavity squamous cell carcinoma (OSCC) cell lines Cal27, OSC19, and SCC25 express epidermal growth factor receptor (EGFR) at high levels with low basal phosphorylated EGFR (pEGFR).

OSCC cell lines have functional EGFR-ERK and EGFR-AKT signaling pathways. At 1 µM, gefitinib reduces AKT and ERK activation in unstimulated and EGF-stimulated cells.

Cisplatin inhibits OSCC cell growth, proliferation, and survival in a dose-dependent manner.

Combination of cisplatin with gefitinib enhances the cytotoxicity of cisplatin. This is associated with increased poly ADP ribose polymerase (PARP) cleavage and increased apoptotic cell populations.