To identify potential prognostic indicators of ovarian cancer and identify targets for therapeutic strategies, mRNA differential display was used to analyze gene expression differences in normal, benign, and cancerous ovarian tissue. One cDNA isolated by this technique, Op18/stathmin, is a highly conserved gene that is reported to have many different functions within a cell, including signal transduction, control of the cell cycle, and the regulation of microtubules. Quantitative Northern blot analysis of 12 malignant ovarian samples, 8 benign ovarian tumors, and 10 normal ovarian tissue samples demonstrated overexpression of Op18/stathmin mRNA in the malignant cancers. Immunohistochemistry showed an apparent overexpression of Op18/stathmin protein level and an association with proliferating cells.