Retinoblastoma (Rb) is a progressive cancer which mainly occurs in children, and which is caused by different genetic or epigenetic alterations that lead to inactivation of both alleles of the RB1 gene.
This is especially important for survivors of heritable cancers such as retinoblastoma (childhood eye cancer), where survivors who carry a germline mutation in the RB1 gene are at increased risk of second cancers in adulthood, and of passing on the disease risk to future offspring.
Hereditary retinoblastoma constitutes a cancer predisposition syndrome: a subject constitutionally carrying an RB1 gene mutation has a greater than 90% risk of developing retinoblastoma but is also at increased risk of developing other types of cancers.Diagnosis is made by fundoscopy.
The der(X) region harboring the RB1 gene was inactivated in a subset of somatic cells, including the retinal cells, in the patient subject which acted as the first hit in the development of her retinoblastoma.
To describe the documented growth, clinical course, and histopathology of retinoblastomas in an untreated and otherwise normal right eye of a 27-year-old white male with a g.153211T>A (p.Tyr606X) mutation in the retinoblastoma 1 gene, whose left eye was enucleated at age 2 years for 2 retinoblastomas.
Analysis of clinical breast cancer samples showed that most of the cells contained two copies of the RB1 gene, even when restriction fragment length polymorphism analysis showed loss of heterozygosity (LOH) at the RB1 locus.