THE ROLE OF DNA REPAIR BY HOMOLOGOUS RECOMBINATION IN ONCOGENESIS

DNA repair by homologous recombination (HR) may be regarded as the two faces of a coin: lowering the oncogenetic potential (precise repair with no consequences on genomic status) or increasing it (deleterious action which may determine chromosome re-arrangements such as loss of heterozigosity). Inherited mutations in genes involved in HR are associated with gene rearrangement and may be a prerequisite for tumor development in some cancer-prone hereditary diseases like Bloom, Werner and Rothmund-Thomson syndromes. Normal eukaryotic cells show some degree of balance between various mechanisms of repair. This review presents the main mechanisms and pathways of homologous recombination repair (synthesis-dependent single strand annealing, constitution of Holliday junctions with their resolution mechanisms and repair by break induced replication), the proteins involved in it and their contribution to oncogenesis.