Figure 1.

POLQ is an important alternative for NHEJ or HR. Upon DSB formation, NHEJ factors inhibit DNA resection and stimulate end joining. When DSB damage is unable to be repaired by NHEJ, 3′ DNA tails are generated from DNA end resection by nucleases. The 3′ DNA tails are processed by TMEJ or BRCA-mediated HR. POLQ becomes more important when NHEJ or HR is not available and repairs DSBs at the expense of introducing mutation signatures. Detection of those signatures in tumor biopsy may be a useful approach to influence treatment decision.