RT Journal Article SR Electronic T1 Expression of Erythropoietin Receptor in Human Merkel Cell Carcinoma of the Eyelid JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 4535 OP 4537 VO 26 IS 6B A1 SATORU KASE A1 KAZUHIKO YOSHIDA A1 MITSUHIKO OSAKI A1 HIRONOBU ADACHI A1 HISAO ITO A1 SHIGEAKI OHNO YR 2006 UL http://ar.iiarjournals.org/content/26/6B/4535.abstract AB Background: Merkel cell carcinoma (MCC) of the eyelid is a rare malignant solid tumor of the elderly, which demonstrates a large, firm, reddish nodule mimicking an angiomatous lesion. The expression of erythropoietin (Epo) and Epo receptor (EpoR), as well as vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR) and basic fibroblast growth factor (bFGF) were examined in human MCC tissues. Materials and Methods: Three patients diagnosed with MCC of the eyelid underwent surgical excision. Isolated tissues were fixed by 4% paraformaldehyde and then were examined using immunohistochemistry. Results: The carcinoma cells consisted of irregular tumor nests with linear stroma and showed hypercellularity indicated by small round nuclei with several mitoses. While immunoreactivity of Epo was undetectable, an increased expression of EpoR was noted in the carcinoma cells. Cytoplasmic immunoreactivity for EpoR was detected in a variety of carcinoma cells, including mitotic cells. VEGF, VEGFR, and bFGF, other angiogenic factors were not expressed in the MCC tissues. Conclusion: EpoR was highly expressed in MCC of the eyelid, suggesting that the Epo-EpoR pathway plays an important role in the formation of MCC. Copyright© 2006 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved