All of them are true about retinoblastoma except

Retinoblastoma (RB) gene has been identified as 14 band on the long-arm of chromosome 13 (13q 14) and is a 'cancer suppressor' or 'antioncogenic' gene. Deletion or inactivation of this protective gene by two mutations (Knudson's two hit hypothesis) results in occurrence of retinoblastoma. Retinoblastoma is commonest tumor of eye in children while in adults it is malignant melanoma of choroid.