TPBG
Encyclopedia
Trophoblast glycoprotein, also known as TPBG or 5T4, is a human gene
.
5T4 is an antigen
expressed in a number of carcinoma
s. It is an N-glycosylated transmembrane 72 kDa glycoprotein
containing seven leucine-rich repeat
regions. 5T4 is often referred to as an oncofetal antigen due to its expression in foetal trophoblast
(where it was first discovered) or trophoblast
glycoprotein
(TPBG).
5T4 is found in tumor
s 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 tumors
throughout their development.
Its confined expression appears to give 5T4 the potential to be useful in cancer immunotherapy
. There has been extensive research into its role in antibody
-directed immunotherapy through the use of the high-affinity murine monoclonal antibody, mAb5T4, to deliver response modifiers (such as staphylococcus aureus
superantigen
) accurately to a tumor.
5T4 is also the target of the cancer vaccine
TroVax
which is used in the treatment of colorectal cancer
.
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
5T4 is an antigen
Antigen
An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...
expressed in a number of carcinoma
Carcinoma
Carcinoma is the medical term for the most common type of cancer occurring in humans. Put simply, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that generally arises from cells originating in the endodermal or ectodermal germ layer during...
s. It is an N-glycosylated transmembrane 72 kDa glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
containing seven leucine-rich repeat
Leucine-rich repeat
A leucine-rich repeat is a protein structural motif that forms an α/β horseshoe fold. It is composed of repeating 20–30 amino acid stretches that are unusually rich in the hydrophobic amino acid leucine...
regions. 5T4 is often referred to as an oncofetal antigen due to its expression in foetal trophoblast
Trophoblast
Trophoblasts are cells forming the outer layer of a blastocyst, which provide nutrients to the embryo and develop into a large part of the placenta. They are formed during the first stage of pregnancy and are the first cells to differentiate from the fertilized egg...
(where it was first discovered) or trophoblast
Trophoblast
Trophoblasts are cells forming the outer layer of a blastocyst, which provide nutrients to the embryo and develop into a large part of the placenta. They are formed during the first stage of pregnancy and are the first cells to differentiate from the fertilized egg...
glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
(TPBG).
5T4 is found in tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
s including the colorectal
Colorectal cancer
Colorectal cancer, commonly known as bowel cancer, is a cancer caused by uncontrolled cell growth , in the colon, rectum, or vermiform appendix. Colorectal cancer is clinically distinct from anal cancer, which affects the anus....
, ovarian
Ovarian cancer
Ovarian cancer is a cancerous growth arising from the ovary. Symptoms are frequently very subtle early on and may include: bloating, pelvic pain, difficulty eating and frequent urination, and are easily confused with other illnesses....
, 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 tumors
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
throughout their development.
Its confined expression appears to give 5T4 the potential to be useful in cancer immunotherapy
Immunotherapy
Immunotherapy is a medical term defined as the "treatment of disease by inducing, enhancing, or suppressing an immune response". Immunotherapies designed to elicit or amplify an immune response are classified as activation immunotherapies. While immunotherapies that reduce or suppress are...
. There has been extensive research into its role in antibody
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
-directed immunotherapy through the use of the high-affinity murine monoclonal antibody, mAb5T4, to deliver response modifiers (such as staphylococcus aureus
Staphylococcus aureus
Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...
superantigen
Superantigen
Superantigens are a class of antigens which cause non-specific activation of T-cells resulting in oligoclonal T cell activation and massive cytokine release...
) accurately to a tumor.
5T4 is also the target of the cancer vaccine
Cancer vaccine
The term cancer vaccine refers to a vaccine that either prevents infections with cancer-causing viruses, treats existing cancer or prevents the development of cancer in certain high risk individuals...
TroVax
TroVax
TroVax is a cancer vaccine being developed by Oxford BioMedica. No cancer vaccines have been proven to cure cancer or extend life yet, but TroVax is recruiting patients for 3 human trials.TroVax uses a tumor-associated antigen, 5T4, with a pox virus vector...
which is used in the treatment of colorectal cancer
Colorectal cancer
Colorectal cancer, commonly known as bowel cancer, is a cancer caused by uncontrolled cell growth , in the colon, rectum, or vermiform appendix. Colorectal cancer is clinically distinct from anal cancer, which affects the anus....
.