Genotypic characteristics of resistant tumors to pre-operative ionizing radiation in rectal cancer

Figure 1 Schematic representations of double-strand break repair by non-homologous end-joining mechanism. The KU proteins are the initial participants in this process as they rapidly bind to broken DNA segments. Another major function of the KU proteins is the active recruitment of DNA-PKcs. DNA-PK activation assists with the recruitment of other proteins involved in the limited DNAend-processing (Artemis, pol m, pol l, and TDK) required to generate ligatable DNA ends. Ligation is mediated by the LIG4/XRCC4 complex and is assisted by the ligation mediator XLF. Once this process is completed, DNA integrity is maintained.