RB1 and astrocytoma (excluding glioblastoma): Deregulation of components of the RB/E2F pathway via genetic and epigenetic changes occurs frequently in most cancer types, including gastrointestinal tract endocrine tumors [28], adenocarcinoma [29, 30], basal cell carcinoma [31], and astrocytomas [6, 32], making it an important target in oncology studies.