Mutation of genes, found in chromosomes, can affect the way in which cells grow and develop within the body. Alterations in<unk> 1 or MYCN can give rise to<unk> .<unk> 1 In children with the heritable genetic form of<unk> , a mutation occurs in the<unk> 1 gene on chromosome 13.<unk> 1 was the first tumor suppressor gene cloned. Although<unk> 1 interacts with over 100 cell proteins, its negative regulator effect on the cell cycle principally arises from binding and inactivation of the transcription factor E2F, thus repressing the transcription of genes which are required for the S phase. The defective<unk> 1 gene can be inherited from either parent; in some children, however, the mutation occurs in the early stages of fetal development. The expression of the<unk> 1 allele is autosomal dominant with 90% penetrance. Inherited forms of<unk> s are more likely to be bilateral. In addition, inherited uni- or bilateral<unk> s may be associated with pineoblastoma and other malignant midline supratentorial primitive neuroectodermal tumors (PNETs) with a dismal outcome;<unk>  concurrent with a PNET is known as trilateral<unk> . A recent meta-analysis has shown that survival of trilateral<unk>  has increased substantially over the last decades. The development of<unk>  can be explained by the two-hit model. According to the two-hit model, both alleles need to be affected, so two events are necessary for the retinal cell or cells to develop into tumors. The first mutational event can be inherited (germline or constitutional), which will then be present in all cells in the body. The second “hit” results in the loss of the remaining normal allele (gene) and occurs within a particular retinal cell. In the sporadic, nonheritable form of<unk> , both mutational events occur within a single retinal cell after fertilization (somatic events); sporadic<unk>  tends to be unilateral. Several methods have been developed to detect the<unk> 1 gene mutations. Attempts to correlate gene mutations to the stage at presentation have not shown convincing evidence of a correlation. MYCN Not all<unk>  cases are with<unk> 1 inactivation. There are cases reported with only one<unk> 1 mutation or even two functional<unk> 1 alleles, which indicates other oncogenic lesions of<unk> . Somatic amplification of the MYCN oncogene is responsible for some cases of nonhereditary, early-onset, aggressive, unilateral<unk> . MYCN can act as a transcription factor and promotes proliferation by regulating the expression of cell cycle genes. Although MYCN amplification accounted for only 1.4% of<unk>  cases, researchers identified it in 18% of infants diagnosed at less than 6 months of age. Median age at diagnosis for MYCN<unk>  was 4.5 months, compared with 24 months for those who had nonfamilial unilateral disease with two<unk> 1 gene mutations.
Retinoblastoma
Ameloblastoma
Mantleoma
Hemangioblastoma
Schwannomatosis
Cementoblastoma
Pinealoma
Brown tumor