Another previous study carried out by Dhawan et al. reported that DPYD and/or TPMT variations were associated with reduced response rates and poorer OS, following a combination of cisplatin and 5-FU treatment in a cohort of 500 cases of patients of north Indian origin with head and neck squamous cell carcinoma [33]. The gene discussed is DPYD; the disease is head and neck squamous cell carcinoma.