TOP2A and extramammary Paget disease: Topo2α protein is commonly expressed across human cancers while TOP2A gene amplification is rare, with only few cancer types (gallbladder and gastroesophageal/esophageal carcinomas) exhibiting TOP2A amplification in >10% of the cases.23 Based on the Topo2α/TOP2A status alone, a substantial proportion of the patients with advanced/metastatic EMPD may benefit from anthracycline‐based chemotherapy.