RB1 and Familial retinoblastoma: Alterations in the RB tumor suppressor gene are important in tumor initiation and early progression of neoplasms, as has been demonstrated in members of families that inherit alterations in RB alleles that predispose them to the development of familial retinoblastoma [97,98,99], as well as in carcinomas of the uterine cervix and oropharynx, in which HPV viruses, via their E7 oncoprotein, inactivate pRb [100,101].