CA125 expression in the tissue of uterine leiomyosarcoma

Background: Elevated serum levels of the epithelial marker CA125 are occasionally observed in leiomyosarcoma (LMS) patients.

To assess the immunohistochemical expression of this marker in the tissue of LMS.

The consecutive unselected records of all patients with LMS diagnosed during the period 1995-2012 were located and abstracted. After verification of the diagnosis, 4 μm unstained slides were prepared from each case for immunohistochemical staining for CA125. Sections of ovarian carcinoma known to express CA125 were used as positive controls.

We located 17 LMS patients from the period under study. Bleeding was the presenting symptom in 9 patients; the diagnosis was established prior to treatment in 11 patients. The tumor was in an advanced stage in 6 patients, and in 7 unstaged patients it was grossly confined to the uterus. Ten patients died within 14 months after the diagnosis. Serum CA125 levels prior to treatment were assessed in only 8 patients and were above normal limits (> 35 U/ml) in 3 of them. Two of the three with elevated serum levels were in stage III, and the third was an unstaged apparent stage I patient. None of the LMS tissue specimens demonstrated immunohistochemical expression of CA125.

CA125 was not immunohistochemically expressed in the tissue of any LMS tumors examined by us. The origin of elevated serum CA125 in some of these tumors is therefore not in its tissue and remains unknown.