<prompt> All of them are true about retinoblastoma exceptRb1 gene is located on 11q14The commonest cause of intraocular calcificationTrilateral retinoblastoma is a combination of bilateral retinoblastoma with pinealoblastomaThe commonest tumour of the eye in children  <response>: 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 Knudsons 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. 