ERBB2 and head and neck squamous cell carcinoma: As noted by Feldman et al. in relation to HNSCC management, data supports the use of specific agents (PIK3CA, PD-1/PD-L1), combination strategies (PIK3CA plus EGFR) or agents approved for other solid tumours such as MGMT (O6-methylguanine DNA methyltransferase) or HER2 (human epidermal growth factor receptor 2) [24].