Fig. 1

The phases of the cell cycle and DNA repair mechanisms active during the four stages. Both classical and alternative non homologous end joining (C-NHEJ and A-NHEJ) repair double strand breaks and are active throughout the cell cycle, they are especially active in G1 [25]. Base excision repair (BER) removes damaged nucleotides and repairs single strand breaks throughout the cell cycle [60]. Nucleotide excision repair is concerned with the removal of bulky damaged DNA lesions and single strand breaks during G1. Mismatch repair corrects DNA mismatches and repairs single strand breaks during S phase [91]. Homologous recombination repairs double strand breaks during S phase and G2 [4]