The role of DNA repair by homologous recombination in oncogenesis.

Abstract 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 rearrangements 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 Hollidayjunctions with their resolution mechanisms and repair by break induced replication), the proteins involved in it and their contribution to oncogenesis.