For example, Zhang et al. found the XRCC1 Arg194Trp polymorphism showed no significant association with CIN and squamous cervical carcinomas (SCC), while the Arg280His polymorphism acted as a protective factor for SCC, and the Arg399Gln polymorphism increased CIN risk among women who first gave birth before 22 years old [14]. Here, XRCC1 is linked to cervical squamous intraepithelial neoplasia.