For example, reduced expression of the centromere protein CENP-E leads to CIN and aneuploidy in vitro and in vivo and while this mildly predisposes mice to haematopoietic and lung malignancies, CENP-E heterozygous mice are more resistant to chemically and genetically induced tumours suggesting that CIN can also act tumour suppressive [13]. This evidence concerns the gene CENPS and cervical squamous intraepithelial neoplasia.