In addition to its well-described role in rare cancers such as retinoblastoma and osteosarcoma [155], RB1 alterations are encountered in a wide variety of cancers: TCGA indicates a high prevalence of RB1 heterozygous deletions in prostate adenocarcinoma (43%), as well as in common (lung squamous carcinoma—49%, breast—37%) and rare cancers (55–56% in kidney chromophobe carcinoma and pediatric osteosarcoma) [154]. The gene discussed is RB1; the disease is pediatric osteosarcoma.