MPO and cancer: Pooled results showed that MPO-463G > A polymorphism were associated with the overall decreased cancer susceptibility in all the genetic models included in this study (additive model: OR = 0.84, 95%CI = 0.76–0.94; allele genetic model: OR = 0.90, 95%CI = 0.840–0.954; recessive genetic model: OR = 0.89, 95%CI = 0.83–0.95).