Increased expression of OCIA domain containing 2 during stepwise progression of ovarian mucinous tumor.

Ovarian cancer immunoreactive antigen domain containing 2 (OCIAD2) has been reported to show cancer-specific expression in early invasive lung adenocarcinoma. OCIAD2 shows high homology with OCIAD1, which was originally immunoscreened from ascites of a patient with ovarian cancer and found to be a tumor-specific protein. Therefore, like OCIAD1, OCIAD2 is expected to show high immunoreactivity in ovarian tumors. In this study, we examined the expression pattern of OCIAD2 in 117 ovarian mucinous tumors, and confirmed that it was more highly expressed in borderline tumor and carcinoma (51/74 cases, 69%) than in adenoma (6/43 cases, 14%). The immunoreactivity of OCIAD2 in borderline tumor and carcinoma was more specific than that of OCIAD1 (adenoma, 21/43 cases, 49%), and more sensitive than that of CEA (borderline tumor and carcinoma, 35/74 cases, 47%). Like OCIAD1, OCIAD2 is a cancer-related protein and its expression level increases during the course of malignant progression and is thought to be a very useful marker for evaluating the malignancy of ovarian mucinous tumors.