Trophoblast glycoprotein, also known as TPBG, 5T4, Wnt-Activated Inhibitory Factor 1 or WAIF1, is a human protein encoded by a TPBGgene.[5] TPBG is an antagonist of Wnt/β-catenin signalling pathway.[6]
5T4 is found in tumors including the colorectal, ovarian, and gastric. Its expression is used as a prognostic aid in these cases. It has very limited expression in normal tissue but is widespread in malignant tumours throughout their development. One study found that 5T4 was present in 85% of a cohort of 72 colorectal carcinomas and in 81% of a cohort of 27 gastric carcinomas.[8]
Its confined expression appears to give 5T4 the potential to be a target for T cells in cancer immunotherapy. There has been extensive research into its role in antibody-directed immunotherapy through the use of the high-affinity murinemonoclonal antibody, mAb5T4, to deliver response modifiers (such as staphylococcus aureussuperantigen) accurately to a tumor.
5T4 is also the target of the cancer vaccineTroVax which is in clinical trials for the treatment of a range of different solid tumour types.
^Starzynska T, Wiechowska-Kozlowska A, Marlicz K, Bromley M, Roberts SA, Lawniczak M, Kolodziej B, Zyluk A, Stern PL (Jun 1998). "5T4 oncofetal antigen in gastric carcinoma and its clinical significance". European Journal of Gastroenterology & Hepatology. 10 (6): 479–84. doi:10.1097/00042737-199806000-00008. PMID9855063. S2CID19687036.
^Awan A, Lucic MR, Shaw DM, Sheppard F, Westwater C, Lyons SA, Stern PL (Jan 2002). "5T4 interacts with TIP-2/GIPC, a PDZ protein, with implications for metastasis". Biochemical and Biophysical Research Communications. 290 (3): 1030–6. doi:10.1006/bbrc.2001.6288. PMID11798178.
Carsberg CJ, Myers KA, Evans GS, Allen TD, Stern PL (Aug 1995). "Metastasis-associated 5T4 oncofoetal antigen is concentrated at microvillus projections of the plasma membrane". Journal of Cell Science. 108. 108 (8): 2905–16. doi:10.1242/jcs.108.8.2905. PMID7593330.
King KW, Sheppard FC, Westwater C, Stern PL, Myers KA (Jun 1999). "Organisation of the mouse and human 5T4 oncofoetal leucine-rich glycoprotein genes and expression in foetal and adult murine tissues". Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression. 1445 (3): 257–70. doi:10.1016/s0167-4781(99)00055-x. PMID10366710.
Awan A, Lucic MR, Shaw DM, Sheppard F, Westwater C, Lyons SA, Stern PL (Jan 2002). "5T4 interacts with TIP-2/GIPC, a PDZ protein, with implications for metastasis". Biochemical and Biophysical Research Communications. 290 (3): 1030–6. doi:10.1006/bbrc.2001.6288. PMID11798178.
Okazaki S, Sekizawa A, Purwosunu Y, Farina A, Wibowo N, Okai T (Nov 2007). "Placenta-derived, cellular messenger RNA expression in the maternal blood of preeclamptic women". Obstetrics and Gynecology. 110 (5): 1130–6. doi:10.1097/01.AOG.0000286761.11436.67. PMID17978129. S2CID24566450.