Abstract: Homologous recombination (HR) is the main way to repair DNA double-stranded breaks, single-stranded DNA gaps and stagnation or folding replication forks, helping to maintain telomeres and ensure the correct segregation of chromosomes during meiosis. Homologous recombination repair (HRR) pathway is one of the DNA damage repair pathways, which has a high mutation frequency in cancers. Besides BRCA1/2 mutations, homologous recombination deficiency (HRD) can also be caused by other mechanisms, such as germline mutations, somatic mutations, genome stability of HRR-related genes and epigenetic modification of HRR genes. The latest clinical data show that reflecting HRD status through HRR gene mutations detection and genomic scar detection can effectively predict the efficiency of poly (ADP-ribose) polymerase inhibitor (PARPi) in patients with cancer and help patients to accurately use drugs and predict the prognosis. However, there are a variety of methods to identify HRD in cancers, the purpose of this paper was to summarize the detection methods of homologous recombination, to explore the value of HRD detection in clinical application, and to lay a foundation for precise treatment of cancer.

Key words: Cancer, Homologous recombination deficiency, Poly (ADP-ribose) polymerase inhibitor, Precision therapy