RNASEH2C and cancer: Finally, RNASEH2C-KAT5 S-AS gene pair was selected for extensive investigation, because this pair met all the criteria above, and both genes in the pair were protein-coding and has molecular function related to genome stability and DNA repair, which have been reported involved in important biological processes such as cancer and aging (Loeb, 2011; Wallace et al., 2012; Lopez-Otin et al., 2013; Moskalev et al., 2013).