XRCC2 and cancer: To further investigate whether the upregulation of XRCC2 at transcriptional level is a consequence of hyperactivated XRCC2 promoter in cancer cells, we cloned the putative human XRCC2 promoter and its 5′UTR sequence, from −2015 upstream to +86 downstream of the transcription start site (Supplementary Figure 1), into a vector containing an EGFP reporter gene (pXRCC2-EGFP) (Fig. 2a).