Overall, the frequencies of abnormal chromosome numbers ranged from ~20 to 55% for SKP1+/− 1 and ~55–80% for SKP1+/− 2, and are consistent with SKP1+/− 2 having a higher level of CIN compared with SKP1+/− 1. This evidence concerns the gene SKP1 and cervical squamous intraepithelial neoplasia.