Retinoblastoma is a rare type of eye cancer that usually occurs in early childhood, usually before the age of five. This type of cancer occurs in the retina, the light-sensitive tissue behind the eye that recognizes light and color. It is the most common type of eye cancer in children. One-third of all retinoblastomas are inherited, meaning that mutations in the RB1 gene are present in all cells in the body, including reproductive cells (sperm or eggs). Patients with inherited retinoblastoma may have a family history of the disease and are at risk of passing on the RB1 mutant gene to the next generation. The other two-thirds of retinoblastomas are non-inherited, meaning that mutations in the RB1 gene are present only in ocular cells and cannot be passed on to the next generation.
The conversion of a proto-oncogene to an oncogene may be caused by a change in the proto-oncogene. This is due to the rearrangement of genes on the chromosome, which causes the proto-oncogene to move to a new location. This event is also caused by an increase in the number of copies obtained from normal proto-oncogenes.
Sometimes a virus enters DNA and enters the proto-oncogene, or approaches it, causing it to become an oncogene. The result of each of these events is a change in the shape of the gene and the cause of the cancer. Retinoblastoma is a rare cancer that progressively and rapidly affects immature retinal cells. Most sufferers are children (usually under 5 years).
One in every 15,000 to 20,000 children develops retinoblastoma. But the prevalence of this disease in adults is very rare. Depending on at what point in time and what part of the gene; If the mutation occurs, the disease will be hereditary (Congenital-Hereditary) and non-hereditary (Non-Hereditary). In 75% of cases, the disease occurs in one eye (Unilateral) and 25% of cases in both eyes (Bilateral), the bilateral type has a more inherited history.