BUB1 and cervical squamous intraepithelial neoplasia: Although CIN is one of the most frequently recognised phenomenon in gastric cancer (Abad et al, 1998; Esteban et al, 1999; Russo et al, 2000), the mitotic checkpoint genes hsMAD2 and hBUB1 are rarely mutated in gastric and other types of human malignancy (Imai et al, 1999; Tanaka et al, 2001).