Full Answer
What does tumor-specific antigens do?
A protein or other molecule that is found only on cancer cells and not on normal cells. Tumor-specific antigens can help the body make an immune response against cancer cells. They may be used as possible targets for targeted therapy or for immunotherapy to help boost the body's immune system to kill more cancer cells.
What are tumor-specific antigens examples?
Examples of tumor-specific antigens include the abnormal products of ras and p53 genes. In contrast, mutation of other genes unrelated to the tumor formation may lead to synthesis of abnormal proteins which are called tumor-associated antigens.
How do you identify a tumor-specific antigen?
Identifying tumor-specific antigens can be tackled using a variety of methods. One could sequence the DNA of cancer and normal cells to search for genomic differences. Alternatively, a researcher could examine the RNA transcripts. Another method is to actually use the immune system of the patient.
What is the difference between tumor-specific antigens and tumor-associated antigens?
Tumor-specific antigens (TSA), found on cancer cells only, not on healthy cells. Tumor-associated antigens (TAA), which have elevated levels on tumor cells, but are also expressed at lower levels on healthy cells.
What are three likely sources of tumor antigen?
Antigens of three classes can induce tumor-specific T cell responses because they display a tumor-specific pattern of expression [30]: antigens derived from viral proteins, antigens derived from point mutations, and antigens encoded by cancer-germline genes (Figure 1).
Where do tumor antigens come from?
Tumor-associated antigens (TAA) can derive from any protein or glycoprotein synthesized by the tumor cell. TAA proteins can reside in any subcellular compartment of the tumor cell; ie, they may be membrane-bound, (more...)
Is HER2 a tumor specific antigen?
The human epidermal growth factor receptor 2 (HER2) represents one of the most studied tumor-associated antigens for cancer immunotherapy. The receptors for HER2 are overexpressed in various human cancers, such as breast and ovarian cancer.
What is TSA in blood?
What It Is. A thyroid stimulating hormone (TSH) test is a common blood test used to evaluate how well the thyroid gland is working. The thyroid gland is located at the lower front of the neck. TSH is produced by the pituitary, a pea-sized gland located at the base of the brain.
What are tumor markers?
A tumor marker is anything present in or produced by cancer cells or other cells of the body in response to cancer or certain benign (noncancerous) conditions that provides information about a cancer, such as how aggressive it is, what kind of treatment it may respond to, or whether it is responding to treatment.
What are the important antigen to produce tumor immunity?
The two most thoroughly characterized oncofetal antigens are carcinoembryonic antigen (CEA) and α-fetoprotein (AFP). Most human and experimental tumors express higher than normal levels or abnormal forms of surface glycoproteins and glycolipids, which may be diagnostic markers and targets for therapy.
What is a tumor rejection antigen?
Tumor rejection antigens are peptides of tumor-cell proteins that are presented to T cells by MHC molecules. These peptides can become the targets of a tumor-specific T-cell response because they are not displayed on the surface of normal cells, at least not at levels sufficient to be recognized by T cells.
What immunotherapies directly target tumor specific antigens?
T-cell immunotherapies targeting unmutated MHC-associated antigens, including viral antigens and tumor-associated antigens (TAA) will also be described in the context of blood cancers.
What are the important antigens to produce tumor immunity?
The two most thoroughly characterized oncofetal antigens are carcinoembryonic antigen (CEA) and α-fetoprotein (AFP). Most human and experimental tumors express higher than normal levels or abnormal forms of surface glycoproteins and glycolipids, which may be diagnostic markers and targets for therapy.
What is a tumor rejection antigen?
Tumor rejection antigens are peptides of tumor-cell proteins that are presented to T cells by MHC molecules. These peptides can become the targets of a tumor-specific T-cell response because they are not displayed on the surface of normal cells, at least not at levels sufficient to be recognized by T cells.
What are tumor markers?
A tumor marker is anything present in or produced by cancer cells or other cells of the body in response to cancer or certain benign (noncancerous) conditions that provides information about a cancer, such as how aggressive it is, what kind of treatment it may respond to, or whether it is responding to treatment.
What is meant by oncofetal antigen?
Oncofetal antigens are substances which are produced by tumors and also by fetal tissues but they are produced in much lower concentration by adult tissues.
What is the reversible binding of antigens to homologous antibodies?
antigen-antibody reaction the reversible binding of antigen to homologous antibody by the formation of weak bonds between antigenic determinants on antigen molecules and antigen binding sites on immunoglobulin molecules. blood-group a's erythrocyte surface antigens whose antigenic differences determine blood groups.
What is the purpose of the carcinoembryonic antigen?
Its primary use is in monitoring the response of patients to cancer treatment.
What is HBeAg?
hepatitis B e antigen(HBeAg) an antigen of hepatitis B virus sometimes present in the blood during acute infection, usually disappearing afterward but sometimes persisting in chronic disease. Anti-HBe antibodies appear transiently during convalescence; they do not protect against reinfection.
What is the H antigen?
H antigen(Ger. Hauch,film), the antigen that occurs in the flagellaof motile bacteria.
What is CD antigen used for?
Its primary use is in monitoring the response of patients to cancer treatment. CD antigen any of a number of cell-surface markers expressed by leukocytes and used to distinguish cell lineages, developmental stages, and functional subsets.
What is CA 125?
cancer antigen 125 (CA 125) a glycoprotein antigen found in normal adult tissues such as the epithelium of the fallopian tubes, the endometrium, the endocervix, the pleura, and the peritoneum. Elevated levels are seen in association with epithelial ovarian carcinomas, particularly nonmucinous tumors, as well as with some other malignancies, ...
Where is flagellar antigen H found?
flagellar antigen H antigen. Forssman antigen a heterogenetic antigen discovered in guinea pig tissues, capable of lysing sheep erythrocytes in the presence of complement. It is found usually in animal organs but occasionally in blood, and induces formation of an antibody (Forssman antibody, a type of heterophile antibody) only when combined ...
What is a tumor specific antigen?
Tumor-specific antigens (TSAs) are unique to tumor cells. TSAs and TAAs typically are portions of intracellular molecules expressed on the cell surface as part of the major histocompatibility complex. Introduction of new genetic information from a virus (eg, human papillomavirus E6 and E7 proteins in cervical cancer)
What are tumor antigens?
Tumor Antigens. Many tumor cells produce antigens, which may be released in the bloodstream or remain on the cell surface. Any molecule capable of being recognized by the immune system is considered an antigen. Antigens have been identified in most of the human cancers, including Burkitt lymphoma, neuroblastoma, melanoma, osteosarcoma, ...
What are antigens in cancer?
Antigens have been identified in most of the human cancers, including Burkitt lymphoma, neuroblastoma, melanoma, osteosarcoma, renal cell carcinoma, ...
Why are antigens buried in the cell membrane?
Uncovering of antigens normally buried in the cell membrane because of defective membrane homeostasis in tumor cells. Release of antigens normally sequestered within the cell or its organelles when tumor cells die. Some recent evidence links immune response in cancer patients to mutations in tumor cells ( 1–4 ).
What is the role of the immune system in tumors?
A key role of the immune system is detection of these antigens to permit subsequent targeting for eradication. However, despite their foreign structure, the immune response to tumor antigens varies and is often insufficient to prevent tumor growth (see also Host Response to Tumors ). Tumor-associated antigens (TAAs) are relatively restricted ...
What is the term for the accumulation of proteins that are normally not expressed or are expressed at very low levels?
Alteration of oncogenes or tumor suppressor genes by carcinogens, which result in formation of neoantigens (novel protein sequences or accumulation of proteins that are normally not expressed or are expressed at very low levels, such as ras or p53), either by generating the novel protein sequence directly or by inducing accumulation of these proteins
What is a tumor specific antigen?
tumor-specific antigen. tumor-specific antigen (TSA) any cell-surface antigen of a tumor that does not occur on normal cells of the same origin. V antigen ( Vi antigen) an antigen contained in the sheath of a bacterium, as Salmonella typhosa (the typhoid bacillus), and thought to contribute to its virulence.
What is a specific antibody?
any substance capable, under appropriate conditions, of inducing a specific immune response and reacting with the products of that response; that is, with specific antibody or specifically sensitized T lymphocytes, or both.
What is the reversible binding of antigens to homologous antibodies?
antigen-antibody reaction the reversible binding of antigen to homologous antibody by the formation of weak bonds between antigenic determinants on antigen molecules and antigen binding sites on immunoglobulin molecules. blood-group a's erythrocyte surface antigens whose antigenic differences determine blood groups.
What is CA 125?
cancer antigen 125 (CA 125) a glycoprotein antigen found in normal adult tissues such as the epithelium of the fallopian tubes, the endometrium, the endocervix, the pleura, and the peritoneum. Elevated levels are seen in association with epithelial ovarian carcinomas, particularly nonmucinous tumors, as well as with some other malignancies, ...
How is conjugated antigenantigen produced?
conjugated antigenantigen produced by coupling a hapten to a protein carrier molecule through covalent bonds; when it induces immunization, the resultant immune response is directed against both the hapten and the carrier.
What is the term for the transformation of infected cells by a virus?
1.any of several antigens, coded for by the viral genome, associated with transformation of infected cells by certain DNA tumor viruses. Called also tumor antigen.
Where is the M antigena located?
M antigena type-specific antigen that appears to be located primarily in the cell wall and is associated with virulence of Streptococcus pyogenes.
What are Tumor-Associated Antigens and Tumor-Specific Antigens?
There are two major classes of tumor antigen which are targeted by T cell immunotherapies – private antigens and public shared antigens. Public shared antigens are common to multiple patients and are split into two categories:
What antibodies are used to kill tumor cells?
Antibodies against TAAs/TSAs are being used to not only directly kill tumor cells primarily by ADCC effects (e.g. rituximab and trastuzumab) but can also serve as diagnostic markers or to innovatively enhance tumor cell targeting of traditional cancer therapies.
What are bispecific antibodies?
Bispecific antibodies have shown great promise for improving clinical efficacy and safety, and there are several marketed drugs that use this approach and many others in clinical development. There are three common types of immunotherapeutic bispecific antibodies: 1 Cytotoxic Effector Cell Redirectors: These redirect T cell cytotoxicity to tumor cells by using bispecific compounds to engage a TAA/TSA and the T cell receptor/CD3 complex. 2 Tumor-targeted Immunomodulators: These are designed to bind to a TAA/TSA and an immunomodulating receptor (e.g. CD40). These compounds are typically intended to be inactive until they bind the tumor antigen, so that the immune stimulation is hyper-localized to the tumor environment, effectively reducing the risk of immune-related side effects. 3 Dual immunomodulators: These bind two different immunomodulating targets resulting in blockade of inhibitory targets, depletion of suppressive cells or activation of effector cells (e.g. PD-1xLAG-3, PD-1xTIM-3, PD-1xCTLA-4, CTLA4xOX40).
Why are immunocompetent mouse models important?
Immunocompetent preclinical mouse models that express human tumor-associated antigens and tumor-specific antigens are in valuable for the research and development of new immunotherapies. A better understanding of the available types of models for assessing TAA/TSA-targeting agents increases the chances that the optimal model for your experimental immunotherapy studies will be selected, therefore providing the best opportunity for success.
What is tumor targeted immunomodulator?
Tumor-targeted Immunomodulators: These are designed to bind to a TAA/TSA and an immunomodulating receptor (e.g. CD40). These compounds are typically intended to be inactive until they bind the tumor antigen, so that the immune stimulation is hyper-localized to the tumor environment, effectively reducing the risk of immune-related side effects.
What is a public shared antigen?
Public shared antigens are common to multiple patients and are split into two categories: Tumor-specific antigens (TSA), found on cancer cells only, not on healthy cells. Tumor-associated antigens (TAA), which have elevated levels on tumor cells, but are also expressed at lower levels on healthy cells.
What is a car T cell?
Chimeric Antigen Receptor (CAR)-T cell therapy uses T cells that are genetically engineered to produce receptors on their surface (known as “chimeric antigen receptors” [CARs]), which allow T cells to target a specific antigen on tumor cells . The first phenomenal success for CAR-T cell therapy was with CD19, a B cell marker that is highly expressed on malignant B cells. Hundreds of CAR-T clinical studies are currently underway, testing against a variety of TAAs/TSAs.
Why is age specific PSA reference range important?
Because a man’s PSA level tends to increase with age, it has been suggested that the use of age-specific PSA reference ranges may increase the accuracy of PSA tests. However, age-specific reference ranges have not been generally favored because their use may delay the detection of prostate cancer in many men.
What is the PSA test?
The PSA test measures the level of PSA in a man’s blood. For this test, a blood sample is sent to a laboratory for analysis. The results are usually reported as nanograms of PSA per milliliter (ng/mL) of blood.
What research has been done to study prostate cancer screening?
Several randomized clinical trials of prostate cancer screening have been carried out. One of the largest is the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, which NCI conducted to determine whether certain screening tests can help reduce the numbers of deaths from several common cancers. In the prostate portion of the trial, the PSA test and DRE were evaluated for their ability to decrease a man’s chances of dying from prostate cancer.
What are tumor markers?
Tumor markers are substances made either by the body in response to cancer or by the cancer itself. Found in blood, urine, and tissue samples, these markers are indicative of a specific disease process and can help doctors distinguish between the types and/or stages of cancer.
How many CA 27.29 tests are able to correctly identify breast cancer?
In fact, a 2007 Journal of Clinical Oncology study reported that less than 60% of CA 27.29 tests were able to correctly identify breast cancer even when the malignancy was positively detected on a PET/CT scan. 5
What is the CA 27.29 test?
The CA 27.29 test is an important tool for monitoring the treatment and care of people with metastatic breast cancer. But it is important to remember that the test has its limitations and is used solely to monitor your response to treatment and/or assess whether a cancer is active or spreading.
Is mammography the best screening for breast cancer?
Instead, routine mammography remains the preferred method of breast cancer screening, whether for new or recurring disease. 6
Can a CA 27.29 be used as a biopsy?
Although tumor marker tests like the CA 27.29 can aid in the management of breast cancer, neither they or any other blood or imaging test can definitively diagnose the disease. Only a breast biopsy can.
Is the breast cancer test less sensitive?
Since that time, numerous studies have shown that the test is far less sensitive than previously thought and that it lacked the specificity to differentiate breast cancer from other benign or malignant causes. 4
Is it safe to use a tumor marker test for breast cancer?
As of November 2007, the American Society of Clinical Oncologists (ASCO) has advised against the use of the tumor marker tests to monitor for recurrence in people with no signs or symptoms of breast cancer.
