Retinoblastoma: genetic background, modern diagnostic methods and therapies

Abstract

Introduction: Retinoblastoma is a rare malignant eye tumor that develops from the embryonic tissue of retina. This disease is one of the classic examples of monogenic diseases. It develops due to a mutation of RB1 gene, which in located on chromosome 13 in the 13q14 locus. It should be noted that about 90% of all cancers of the eyes in children under 5 years of age are caused by RB1 mutations. Thus the study of modern methods of diagnosis and treatment of retinoblastoma can be effectively applied as a model for the treatment of other cancers caused genetically.

Material and Methods: In this study we performed a comprehensive review of medical data for the last 10 years using PubMed, Scopus and IBN to study the incidence, prevalence, causes, symptoms, and modern methods of treatment of this disease.

Discussion results: There is no doubt that the main cause of this disease is different mutations in both alleles of the retinoblastoma tumor suppressor gene - RB1, or a mutation in one allele, but with obligatory deactivation of another. About 60% of retinoblastomas are not hereditary, and in most cases are unilateral, with a medium age of diagnosis being 2 years. Retinoblastoma can also be bilateral and hereditary (40% of cases), with an earlier medium age of diagnosis being 1 year. The disease is characterized by a variety of symptoms, among which the most important are the leykokoriya and strabismus. International common classification system of the severity of the disease allows the implementation of general procedures for the treatment of disorder according to the degree of its development. Current trends in the treatment are aimed at maximum preservation of the patients vision, and include techniques such as cryotherapy, laser and transpupillary thermotherapy treatment along with the standard radiation therapy. Genetic diagnosis methods include PCR analysis, DNA sequencing, Southern blot method, and allow to reveal the problem at an early stage of development. During the period from 1991 to 2004, in Moldova were registered 37 children with retinoblastoma, representing 1.26% of the total number of children with malignant tumors in a given time.

Conclusion: Retinoblastoma is the most common type of eye cancer in children. However, with early detection, sequential treatment and strict compliance with the doctor's recommendations, it is possible to preserve the vision in 75% of cases. The introduction into medical practice of genetic diagnosis and genetic counseling of families is appropriate, as this helps to reduce the mortality and morbidity in patients due to early detection of problems and their early treatment.