NOTCH1 and neoplasm: Of 138 insertion sites identified in 108 Notch1-trapped SB tumours, 136 (98.6%) were concentrated between exon 25 and exon 30 (Fig. 3b), and 73.5% (100/136) were in the same direction as the direction of gene expression, indicating that the transposon specifically inserted to result in overexpression of ICN1.