TLR3 and head and neck squamous cell carcinoma: HIV-infected T-cell exosomes quickly enter recipient cells via epidermal growth factor receptor (EGFR) and subsequently stimulate ERK1/2 (extracellular signal-regulated kinase 1 and 2) phosphorylation in HNSCC and lung cancer cells in an EGFR/Toll-like receptor 3 (TLR3)-dependent manner.