Detection of Merkel Cell Polyomavirus in Human Tumors and Sarcoidosis From Formalin-Fixed Paraffin-Embedded (FFPE) Tissue Samples

Abstract

Purpose: The purpose of our project is to determine the presence of Merkel cell polyomavirus (MCPyV) in different tumor types and sarcoidosis. Introduction: MCPyV was recently shown to be present in 80%-100% of Merkel cell carcinomas (MCC) and is considered an oncogenic driver of this tumor. Our goal is to survey a variety of tumor types with a novel antibody (Ab3), which has been shown in literature to have increased sensitivity in detection of MCPyV. We also examined if the virus plays a role in the development of sarcoidosis. Methods: We collected 107 FFPE samples using the electronic medical record at UTMC. There were 24 endometrial carcinomas, 20 intraductal breast carcinomas, 18 neuroendocrine tumors, 15 gastrointestinal stromal tumors, 11 Merkel cell tumors, 8 lobular breast carcinomas, 8 myxomas, and 3 sarcoid granulomas. Hematoxylin and eosin stained slides from the tumors were reviewed, and tissue microarrays were assembled. A cell line (MS-1) extracted from adrenal metastases of MCC was used as a control. The Ab3 mouse antibody that targets fragments of the large T antigen was used to detect presence of MCPyV through immunohistochemistry (IHC) staining method. Results: Upon review of IHC staining 90.9 %( 10/11) of Merkel cell carcinomas, 5.6% (1/18) of neuroendocrine carcinomas, and 4.2% (1/24) of endometrial carcinomas were positive for MCPyV, and there was no detection of MCPyV in GIST, sarcoid, intraductal, or lobular breast carcinoma, or myxomas. Conclusions: MCPyV is strongly associated with MCC and was present in 2 other tumors. While mechanisms of how this virus causes cancer are still being elucidated, such a ubiquitous virus may also be associated with other tumors. Our study, while small in sample size, showed that other neuroendocrine tumors and endometrial carcinomas might also have an association with MCPyV virus.