MUC1 and duodenal adenocarcinoma: Three patients, 2 with metastatic ampullary adenocarcinoma and 1 with duodenal adenocarcinoma with positive IHC staining for CK7 or MUC1 who failed 2 lines of chemotherapy with oxaliplatin, irinotecan, and 5FU received nab‐paclitaxel and gemcitabine with or without cisplatin.