Tumor tissue CA125 in ovarian carcinoma patients with normal serum levels

A good correlation between elevated serum CA125 and its immunolocalization in ovarian tumor tissue has been reported. This study was undertaken in order to assess the presence of CA125 in tumor tissue obtained from ovarian carcinoma patients with normal serum levels. Eleven such ovarian carcinoma patients (nine of them serous) were identified. In seven the level was normal prior to the initial operation, and in four, prior to a positive second-look operation. Immunohistochemical staining of paraffin sections for CA125 was positive in seven of the tumor tissue samples. Tumor tissue of most ovarian carcinoma patients with a preoperative normal serum CA125 contains the antigen, but an undetermined mechanism prevents elevated serum levels.