XRCC1 and systemic sclerosis: Vlachogiannis et al. [113] discovered that increased DNA damages in SSc patients under cytotoxic treatment were displayed as increases in oxidative stress and abasic sites, defective DSB/R (denoted by downregulation of MRE11A and PRKDC) and base excision repair (denoted by PARP1 and XRCC1), and the upregulation of apoptosis-related genes (BAX and BBC3).