Hansen et al. (1985) and Dryja et al. (1986) subsequently demonstrated that osteosarcoma—one of the common second primary cancers to affect patients who carry a pathogenic variant in RB1—also showed somatic loss of heterozygosity in the region of chromosome 13 that contains the RB1 locus in patients both with and without retinoblastoma. Here, RB1 is linked to osteosarcoma.