XPC and cancer: Since a key factor for stem cell quiescence is the reduction in replication errors, any impairment in this process could contribute to tumorigenesis.To explore these ideas, we performed a combination of proximity ligation assays (PLA) and MECP2/XPC immunofluorescence stainings to show interaction between MECP2 and XPC, specifically in normal human quiescent basal cells which become progressively lost during progression from normal to cancer (Figure 7A, Supplementary Table S8 for overview of procedure).