GSTM1 and head and neck squamous cell carcinoma: Peter et al. [38] also reported that the GSTM1-null genotype was associated with an increased risk for HNSCC (OR = 1.3, 95% CI 1.0–1.6) while also observing a higher risk in heavy smokers (OR = 4.2, 95% CI 1.6–4.3) with deletion compared to subjects without (OR = 2.6, 95% CI 1.6–4.3).