Background: Cytokeratins are constituents of the intermediate filaments of epithelial cells which are expressed in various combinations depending on the epithelial type and the degree of differentiation. Using the reverse transcriptase-polymerase chain reaction technique (RT-PCR) we recently demonstrated that: (1) Cytokertin 20-the most recent discovered cytokeratin-is expressed in endometrial carcinoma tumors but not in the endometrium of patients with benign diseases, and (2) CK-20 is not expressed in blood cells. The aim of this study is to examine whether CK-20 expression in blood can be used as a biomarker for the detection of the dissemination of malignant cells in patients treated for endometrial carcinoma.
Methods: In the present study, we have used RT-PCR to determine the expression of CK-20 in the peripheral blood of the following groups: (1) preop new diagnosed patients (n = 20), (2) patients with no clinical evidence of disease following completion of definitive treatment (n = 33; 17 at low risk; 16 at high risk), (3) patients with recurrent disease (n = 6), and (4) a control group of healthy subjects (n = 16). RNA was extracted from cell pellets and analysed by RT-PCR using primers for CK-20.
Results: Of the 20 patients of the first group 7 (35%) were CK-20 positive. Of the 33 patients of the second group 17 (51%) were CK-20 positive. Subdivision of this group showed that 9 of 17 (53%) were positive in the low-risk subgroup, and 8 of 16 (50%) were positive in the high-risk subgroup. All 6 patients with recurrent disease were positive, and all subjects in the control group were negative.
Conclusion: These results indicate that RT-PCR of CK-20, because of its high sensitivity, is a potential biomarker for detecting metastasis in blood samples of patients with endometrial carcinoma.
Copyright 2000 Academic Press.