According to previous studies, including ours6,7,9–13, 46–70% of clear cell carcinomas and 30–46% of endometrioid carcinomas harbor ARID1A mutations, and immunohistochemical analysis has demonstrated that ARID1A loss-of-function mutations are strongly correlated with the loss of ARID1A protein expression in endometriosis-associated ovarian cancer6,7. The gene discussed is ARID1A; the disease is endometrioid adenocarcinoma.