Why is retinoblastoma more common in individuals who have inherited the RB deletion and have the genetic predisposition for retinoblastoma?

Retinoblastoma is more common in people due to the mutation of RB gene in them.

Explanation:

Retinoblastoma is a disease that affects the eyes of an individual. It is more commonly eye cancer which occurs on the retina of the eye. Retinoblastoma mainly affects younger children.

When the RB gene is mutated or it is deleted already on any one of a homologous chromosomes, then only one hit rather that two which is needed to cause the development of retinoblastoma and hence the probability is of retinoblastoma to occur is higher in the individuals who have already inherited the RB deletion and also have a genetic predisposition for the retinoblastoma.