For example, decreased serum PON1 activity and increased levels of lipid peroxidation have been reported in 45 Pakistani patients with oral squamous cell carcinoma [29], and 30 Turkish patients with esophageal squamous cell carcinoma [30], and a further 25 Turkish patients with papillary thyroid cancer [31]. This evidence concerns the gene PON1 and esophageal squamous cell carcinoma.