ARID1A and adenocarcinoma: Molecular studies indicate that PRKD1-3 rearrangements, including ARID1A-PRKD1 and DDX3X-PRKD1 gene fusions, are seen in about 80% of CAMSG in contrast to polymorphous adenocarcinomas with classical morphology where less than 10% of cases show these changes (26).