XRCC1 and cancer: Genetic variations, i.e. polymorphism of DNA repair enzymes and cofactors, 8-oxoguanine DNA glycosylase (OGG1) [48, 49], APE1 [50], X-ray repair cross-complementing protein 1 (XRCC1) [51–53], XPC [54, 55], MSH3 [56–59], RPA-CDK7 [60] among others have been reported to be associated with cancer and neurodegenerative diseases.