RB1 and cancer: Insertion of Alu elements into DNA repair genes such as breast cancer 1 genes (BRCA1) and 2 (BRCA2) [19,48], LINE-1 retrotransposon into tumor suppressor gene adenomatous polyposis coli (APC) [20], and retinoblastoma 1 (RB1) gene [49] cause disruption in the function of these genes, thus leading to tumorogenesis.