OBJECTIVE: 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. The recently identified cytokeratin-20 (CK-20) was found with immunohistochemical methods to be expressed in gastrointestinal epithelium, uroepithelial cells, and Merkel cells. Clues were also found for low expression of CK-20 in endometrial carcinoma cells. The aim of this study was to examine whether CK-20 expression can be measured in endometrial carcinoma with the more sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) methods and therefore used as a potential diagnostic tumor biomarker for endometrial carcinoma. METHODS: In the present study we have used RT-PCR methods to determine expression of CK-20 in endometrial epithelial cells. Endometrial specimens were collected from 18 patients with endometrial carcinoma and 22 patients that underwent hysterectomy due to benign diseases. The specimens were prepared for both RT-PCR and immunohistochemical analysis. RNA, of the various cell pellets, was extracted and RT-PCR was performed with CK-20 and CK-19 primers (CK-19 was used as a marker for normal epithelial cells). Immunohistochemistry was carried out with the avidin-biotin-peroxidase complex method on formalin-fixed paraffin sections using CK-20 antibody. RESULTS: CK-20 amplification band (370 bp) was obtained with mRNA extracted from endometrial carcinoma cells of 17 of the patients with endometrial carcinoma (sensitivity, 94.4%). CK-20 was negative in 21 patients with benign endometrial disease (specificity, 91.3%). No positive results were obtained with the immunohistochemical methods. CONCLUSION: These results indicate that RT-PCR of CK-20, because of its high sensitivity, is a potential biomarker for detecting endometrial carcinoma. Copyright 1998 Academic Press.
OBJECTIVE: 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. The recently identified cytokeratin-20 (CK-20) was found with immunohistochemical methods to be expressed in gastrointestinal epithelium, uroepithelial cells, and Merkel cells. Clues were also found for low expression of CK-20 in endometrial carcinoma cells. The aim of this study was to examine whether CK-20 expression can be measured in endometrial carcinoma with the more sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) methods and therefore used as a potential diagnostic tumor biomarker for endometrial carcinoma. METHODS: In the present study we have used RT-PCR methods to determine expression of CK-20 in endometrial epithelial cells. Endometrial specimens were collected from 18 patients with endometrial carcinoma and 22 patients that underwent hysterectomy due to benign diseases. The specimens were prepared for both RT-PCR and immunohistochemical analysis. RNA, of the various cell pellets, was extracted and RT-PCR was performed with CK-20 and CK-19 primers (CK-19 was used as a marker for normal epithelial cells). Immunohistochemistry was carried out with the avidin-biotin-peroxidase complex method on formalin-fixed paraffin sections using CK-20 antibody. RESULTS:CK-20 amplification band (370 bp) was obtained with mRNA extracted from endometrial carcinoma cells of 17 of the patients with endometrial carcinoma (sensitivity, 94.4%). CK-20 was negative in 21 patients with benign endometrial disease (specificity, 91.3%). No positive results were obtained with the immunohistochemical methods. CONCLUSION: These results indicate that RT-PCR of CK-20, because of its high sensitivity, is a potential biomarker for detecting endometrial carcinoma. Copyright 1998 Academic Press.