In fact, concurrent upregulation of ABC transporters, metabolic activity and antioxidant protection has recently been observed in the side population of a head and neck squameous cell carcinoma (HNSCC) mutant; here, cellular GSH levels were higher in cisplatin-resistant p53mut_c cells, consistent with a higher capacity to fend off cytotoxic oxidative effects such those caused by cisplatin treatment [34]. This evidence concerns the gene ABCG2 and head and neck squamous cell carcinoma.