Some of them are reported to share the same oncogenes, as WT1 in Wilms' tumour (Maiti et al, 2000), in retinoblastoma (Wagner et al, 2002) and in acute myeloid leukaemia (King-Underwood et al, 1996), and RB1 in retinoblastoma (Sanchez et al, 2000), neuroblastoma (Markaki et al, 2001), childhood leukaemia (Markaki et al, 2001) and Ewing's sarcoma (Cope et al, 2001). Here, RB1 is linked to retinoblastoma.