Placental type alkaline phosphatase tissue expression in ovarian serous carcinoma

OBJECTIVE: To analyze the expression profile of placental type alkaline phosphatase (PLAP), cancer antigen 125 (CA125), and human epididymis protein 4 (HE4) in serous ovarian cancer and to correlate their expression with the tumor aggressiveness and progression. METHODS: Retrospective study considering a tissue microarray of 82 women affected by ovarian serous cancer. Protein expression was assessed by immunohistochemistry on ovarian serous cancer tissue samples. Immunohistochemical staining was semiquantitatively evaluated as H-score. RESULTS: Median H-score values were lower for PLAP, 1 (IQR 0-4) than CA125, 10 (IQR 6-12) or HE4, 8 (IQR 5-12). Even if PLAP was less expressed in the cells of serous ovarian cancer than CA125 or HE4 it was relatively more expressed in the fourth quartile of its H-score distribution among cases with low CA125 or HE4 expression. Furthermore, PLAP and HE4 high expression resulted to be significantly correlated with a better prognosis. CONCLUSIONS: PLAP could be an additional marker for early detection of serous ovarian carcinoma, together with the established CA125 and HE4. In addition, PLAP expression is correlated with prognosis, giving, in this way, an additional tool for improving treatment approach.