Table 2. Twenty-two genes involved in the NHEJ pathway and their associated functions.

Gene(HUGO)	Function
APLF	Chromatin-binding checkpoint protein [36]
ATM	DSB signaling [37]
DCLRE1C	End-processing [38]
LIG4	Main DSB ligating enzyme [39]
MDC1	DSB signaling; recruits DNA damage response elements [40]
MRE11A	DSB signaling of MRN complex [41]
NBN	DSB signaling of MRN complex [42]
NHEJ1	Ligase accessory factor [43]
PARG	Catabolism of PAR [44]
POLM	Polymerase; gap-filling [45]
PRKDC	DSB signaling; DNA-dependent protein kinase catalytic subunit [46]
RAD50	DSB signaling; MRN complex [47]
RNF168	DSB signaling; 63-linked histone poly-ubiquitination of H2AX; (downstream RNF88, upstream BRCA1) [48]
RNF8	Ubiquinates H2AX [49]
TP53BP1	DSB signaling [50]
XRCC2	DNA break and crosslink repair [51]
XRCC3	DNA break and crosslink repair [51]
XRCC4	Ligase accessory factor [52]
XRCC5	Binds to DSB end/Ku heterodimer [53]
XRCC6	Binds to DSB end/Ku heterodimer [54]
H2AFX	DSB signaling [55]