ARID1A and endometriosis: For example, some known somatic driver mutations in the genes ARID1A, PIK3CA, KRAS, and PPP2R1A have been found in the endometriotic lesions of 19 of 24 patients with deep-infiltrating endometriosis even though this form of endometriosis almost never undergoes malignant transformation (Anglesio et al. 2017; Dawson et al. 2018).