MedGen

A spectrum of non-invasive neoplastic lesions that arise from the terminal ductal lobular units of the breast. There is atypical small epithelial cell proliferation. Pagetoid involvement of the terminal ducts may or may not be present. In the minority of cases, there is a risk for subsequent development of invasive ductal or invasive lobular carcinoma. [from NCI]

Retinoblastoma is a malignant tumor of the developing retina that occurs in children, usually before age five years. Retinoblastoma develops from cells that have cancer-predisposing variants in both copies of RB1. Retinoblastoma may be unifocal or multifocal. About 60% of affected individuals have unilateral retinoblastoma with a mean age of diagnosis of 24 months; about 40% have bilateral retinoblastoma with a mean age of diagnosis of 15 months. Heritable retinoblastoma is an autosomal dominant susceptibility for retinoblastoma. Individuals with heritable retinoblastoma are also at increased risk of developing non-ocular tumors. [from GeneReviews]