Four of the seven networked CIS genes have recently been identified as MB CISs ina tissue-specific SB mutagenesis screen of primary tumours generated using thePtch model (Crebbp, Nfia, Nfib andTead1[30]), and orthologs of a further three genes within our network(Dip2c, Edil3 and Erbb4) were identified as MBCISs in the same screen. This evidence concerns the gene NFIB and in situ carcinoma.