In mice, Robo1 inactivation produces delayed lung maturation and bronchial hyperplasia (Xian et al, 2001) and we have demonstrated de novo ROBO1 promoter methylation in 19% primary invasive breast carcinomas and 18% primary clear cell RCC, although somatic mutations were not identified (Dallol et al, 2002b). This evidence concerns the gene ROBO1 and invasive breast carcinoma.