A previous report, which was conducted with pterygium tissue, found higher expression of GSTP1 and GSTT1 than in control healthy patients.23Similarly, GSTA, GSTT1, and GSTM4 expressions were stronger in non-small cell lung cancer cells than normal lung epithelium.24Also, larynx cancer tissue had increased expression of GSTP than that of normal controls.25In another study, the expression of CYP1A1 and GSTP1 isozymes were found statistically significantly higher in patients who had an aortic aneurysm than in control groups.14 This evidence concerns the gene CYP1A1 and pterygium.