Description : Retinoblastoma (RB) is an embryonic malignant neoplasm of retinal origin. It almost
always presents in early childhood and is often bilateral. Spontaneous regression
('cure') occurs in some cases. The retinoblastoma gene (RB1) was the first tumor suppressor
gene cloned. It is a negative regulator of the cell cycle through its ability to bind
the transcription factor E2F (189971) and repress transcription of genes required
for S phase (Hanahan and Weinberg, 2000).;