Adrenal 4-binding protein in common epithelial and metastatic tumors of the ovary.

Adrenal 4-binding protein (Ad4BP) is a transcription factor that regulates the expression of steroidogenic enzymes. Ovarian tumors other than sex cord stromal tumors are occasionally associated with functioning stroma or hormonal abnormalities. To determine the steroidogenic potential of these tumors, the authors determined the immunohistochemical distribution of Ad4BP in 75 patients with primary common epithelial tumors (20 cystadenomas, 15 carcinomas of low malignant potential, and 40 carcinomas), and seven patients with metastatic carcinoma of the ovary. Ad4BP immunoreactivity was observed in intratumoral stromal cells in 3 of 15 (20%) carcinomas of low malignant potential, 26 of 40 (65%) carcinomas, and three of seven (43%) metastatic carcinomas. Ad4BP immunoreactivity was not observed in the stroma of cystadenomas. Among the positive cases, Ad4BP-positive stromal cells were particularly distributed adjacent to invasive carcinomatous glands. Among ovarian carcinomas, mucinous carcinoma showed a significantly higher number of Ad4BP-positive intratumoral stromal cells than did other histological types. Results suggest that invasion of primary or metastatic carcinoma into the ovarian stroma, especially in the case of mucinous carcinoma, may render the stromal cells to acquire the potential of metabolizing and synthesizing steroid hormones.