5T4 Oncofetal Trophoblast glycoprotein

5T4 is a N-glycosylated transmembrane 72 kDa (420 AA) glycoprotein containing seven leucine-rich repeat regions. 5T4 is often referred to as an oncofetal antigen due to its expression in fetal trophoblast where it was first discovered or trophoblast glycoprotein (TPBG). 5T4 oncofetal antigen is defined by a monoclonal antibody originally raised against human placental trophoblast and which recognizes a 72 kD glycoprotein expressed in a variety of different carcinomas but detected only at very low levels in normal epithelia. Patterns of expression of 5T4 oncofetal antigen in colorectal carcinomas indicate a significant association with tumor metastasis. By IHC, 71% of the carcinomas demonstrate positive 5T4 immunoreactivity in adenocarcinoma cells and/or associated stromal tissue.5T4 is found in tumors including the colorectal, ovarian, and gastric. Its expression is used as a prognostic aid in these cases. 5T4 is widespread in malignant tumors throughout the various stages of their development.In assessing the 5T4 phenotype it has been determined that there is a significant correlation between 5T4 expression and advanced stage of disease (FIGO stages III and IV) (P < 0.001) and with poorly differentiated tumors (P = 0.036) compared to well or moderately differentiated tumors. Patients with tumors expressing 5T4 were are likely to respond well to adjuvant therapy and have a significantly worse outlook in terms of survival and disease-free interval.