DNA repair is an important defense mechanism against DNA damage and includes four distinct pathways: direct, excision, mismatch, and double-strand break repair systems. Recent evidence suggests that alterations in proteins participating in the DNA repair systems may result in cellular senescence, cell death, and neoplastic transformation. Malignancies in adulthood exhibit genomic instability and an increased mutation rate due to underlying defects in DNA repair. However, our knowledge on DNA repair defects, both in germline and somatic mutations, and their relationship with childhood malignancies remains incomplete. Mutations, gene deletions, and inversions in various DNA repair genes have been reported and special attention has recently been focused on the interaction between these abnormalities and malignant transformation in childhood. The purpose of this review is to summarize the existing clinical information concerning components of the DNA repair systems and their influence on the development of the most common pediatric malignancies, including leukemia, tumors of the central nervous system, rhabdomyosarcoma, and retinoblastoma. Such information could possibly explain the response or resistance to chemotherapy and the possible risk of relapse in childhood malignancies presenting specific DNA repair defects. Additionally, these data could be beneficial for the development of novel therapeutic strategies.

Keywords: Retinoblastoma - metabolism, Rhabdomyosarcoma - metabolism, Polymorphism, Genetic, Retinal Neoplasms - metabolism, Mutation, Neoplasms - metabolism, Leukemia - metabolism, DNA Mismatch Repair, DNA Repair - physiology, DNA Damage, Child, Central Nervous System Neoplasms - metabolism