In addition, ovarian cancer associated with endometriosis is correlated with the same molecular features that are present in endometriosis (particularly in the atypical variant) and type 1 ovarian cancer, such as PIK3CA and KRAS activating mutations and ARID1A and PTEN inactivating mutations, although there are differences in the frequency of these alterations between the two subtypes of ovarian cancer. Here, PIK3CA is linked to endometriosis.