PIK3CA and cervical squamous intraepithelial neoplasia: Moreover, mutations of a group of specific tumor suppressor genes and oncogenes, such as KRAS, PIK3CA, APC, TP53, and so forth, are found to accumulate in CRCs with the typical karyotypic abnormalities caused by CIN (Colussi et al., 2013), though it remains unclear whether these mutations initiate CIN or vice versa.