Aileen Houston, John M. Williams, Tihana Lenac Rovis, Daniel K. Shanley, Ronan T. O'Riordan, Patrick A. Kiely, Melanie Ball, Orla P. Barry, Jacquie Kelly, Aine Fanning, John MacSharry, Ofer Mandelboim, Bernhard B. Singer, Stipan Jonjic & Tom Moore

2016

February

mAbs

Pregnancy-specific glycoprotein expression in normal gastrointestinal tract and in tumors detected with novel monoclonal antibodies

Published

()

Oesophagus, squamous epithelium, squamous cell carcinoma, colon, colonic adenocarcinoma, pregnancy-specific glycoprotein, PSG1, carcinoembryonic antigen, CEACAM, placenta, trophoblast, monoclonal antibody

8

2

405

413

Pregnancy-specific glycoproteins (PSGs) are immunoglobulin superfamily members related to the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family and are encoded by ten genes in the human. They are secreted at high levels by placental syncytiotrophoblast into maternal blood during pregnancy, and are implicated in immunoregulation, thromboregulation, and angiogenesis. To determine whether PSGs are expressed in tumors, we characterized 16 novel monoclonal antibodies to human PSG1 and used two that do not cross-react with CEACAMs to study PSG expression in tumors and in the gastrointestinal (GI) tract using tissue arrays and immunohistochemistry. Staining was frequently observed in primary squamous cell carcinomas and colonic adenocarcinomas and was correlated with the degree of tumor differentiation, being largely absent from metastatic samples. Staining was also observed in normal oesophageal and colonic epithelium. PSG expression in the human and mouse GI tract was confirmed using quantitative RT-PCR. However, mRNA expression was several orders of magnitude lower in the GI tract compared to placenta. Our results identify a non-placental site of PSG expression in the gut and associated tumors, with implications for determining whether PSGs have a role in tumor progression, and utility as tumor biomarkers.

1942-0862