1. A 45-year-old woman with a history of familial adenomatous polyposis (FAP) presents with abdominal pain. She undergoes a distal pancreatectomy for a 4 cm mass in the tail of the pancreas. The mass is well-circumscribed and has a dense white fibrous cut surface. Microscopically, the tumor is composed of a cellular population of bland fibroblastic cells in a collagenous stroma. What is the most likely immunohistochemical profile of the tumor?