ARID1A and endometrioid adenocarcinoma: With frameshift mutations in ARID1A, an activating missense mutation in PIK3CA (R38C) (ref. 45) and an inactivating missense mutation in PTEN (Y155C) (ref. 46), IGROV1 not only has the overall genomic profile but also several specific signature mutations of endometrioid carcinoma.