Another line of evidence for human relevancederives from genetic variation in oxidative-stress related genes andcancer susceptibility in the human population.18 Single nucleotide polymorphisms (SNPs) in antioxidant enzymesSOD and catalase (CAT) have been linked to increased cancer incidenceand susceptibility.110 Moreover, SNPs alteringthe function of AP-endonuclease 1 (APE1) and 8-oxo-guanine DNA glycosylase(OGG1), DNA repair genes primarily involved in base excision repairof oxidative DNA damage,18 have been linkedto increased cancer risk in humans.111−113. This evidence concerns the gene CAT and cancer.