EGFR and head and neck squamous cell carcinoma: Several studies have also documented that the other two amino acid transporters ASCT2 and xCT mediate chemotherapy and EGFR-targeted therapy resistance in HNSCC cells after treatments of CDDP, cetuximab and AG1478 [132,133,134], implying that amino acid transporters could be a therapeutic target in patients with HNSCCs.