Immunohistochemical similarities between pancreatic mucinous cystic tumor and ovarian mucinous cystic tumor.

OBJECTIVE: Pancreatic mucinous cystic tumor (MCT(P)) and ovarian mucinous cystic tumor (MCT(O)) show common features. However, there are few studies showing a comparison of both types of tumor. We immunohistochemically studied both types of tumor to clarify their characteristics.
METHODS: Eight patients with MCT(P) and 21 patients with MCT(O) were examined. The tumors were immunohistochemically examined using antibodies against female sex hormone receptors (estrogen receptor, progesterone receptor, and alpha-inhibin), pancreatobiliary tissue markers (carbohydrate antigen 19-9 and DUPAN2) and cell cycle regulators (p27kip1 and phosphorylated retinoblastoma). Samples from 7 female patients with invasive pancreatic ductal carcinoma (DC), 8 female patients with normal pancreatic tissue, and 10 patients with normal ovarian tissue were also examined.
RESULTS: In the tumor epithelial cells, the expressions of DUPAN2 and p27/kip1 were similar between MCT(P) (38% and 88%, respectively) and MCT(O) (14% and 76%, respectively), but significantly different between both tumors and DC (100% and 0%). In the stromal cells, the expressions of estrogen receptor, progesterone receptor, alpha-inhibin, and p27/kip1 were similar between MCT(P) (63%, 75%, 50%, and 63%, respectively) and MCT(O) (57%, 71%, 81%, and 57%, respectively), but significantly different between both tumors and DC (0%, 0%, 0%, and 0%, respectively).
CONCLUSIONS: MCT(P) and MCT(O) have several immunohistochemical similarities and are significantly different from DC. The female sex hormone system may play a major role in the development of both MCT(P) and MCT(O). A frequent p27/kip1 expression level was associated with nonaggressive progression of both tumors.