New Techniques Used in Genetic Testing - Term Paper Example

New Techniques Used In Genetic Testing Name Institution Date New Techniques used in Genetic Testing Introduction Genetic testing is usually used in detecting the occurrence of cancer in an individual by predicting the possibility of one developing cancer at some point in time. It is otherwise called predictive testing. It usually involves the analysis of one’s genes, proteins or chromosomes to predict the likelihood of a disease or condition through acquired karyotypes, mutations, genotypes or phenotypes. This will help in identifying the risk in an individual and establish the diagnoses or prognoses for the same individual. Currently there are about 62 genetic tests for 9 different cancers (Chin et al., 2006). New methods are however being developed to supplement the already existing ones. This paper will look to explain some of the new techniques used in carrying out genetic testing for cancer. Gene variants that are related to a certain condition or even disease can be detected in genetic testing. Factors that would drive one to consider doing a genetic test include the following: There are signs of a disease, High risk of getting the disease is suspected in future, One suspects passing the disease to their children, One is pregnant and would like the fetus tested. The outcome of the results will not only help in diagnosis of a disease but also in establishing how far the disease has spread and in getting the selection of medicines to either cure or manage it. The tests are done on tissues obtained from the body, such as the skin tissue, mouth cells, hair, blood tissues, tumors and fetal fluid during pregnancy. Tests are done to check any changes in the DNA and the outcome discussed by the physician and patient. According to Eng and Viig, (1997), there are two main categories of genetic testing techniques; viz screening and scanning methods. Specific genes are screened to check for mutations identified previously. However, for diseases with many disease causing mutations that locate at any point in the gene’s coding region, screening would be unrealistic. Such a case is breast cancer whose mutations appear at any point in the large BRCA1 and BRCA2 genes. This would therefore call for a separate DNA probe on every mutation and this is expensive and time consuming. Scanning on the other hand involves carrying out tests on the genes without considering any mutations that might have existed previously. However, this means that it is the coding regions only that will be scanned. Other mutations in the regulatory regions that could interact with the disease causing genes are excluded. New techniques under development Alpha Catenin test Alpha Catenin test is also called Methylation marker test. It is used in foreseeing of breast cancer. It involves suppression of the tumor to control the buildup of cells by minimizing activities and localization of the transcriptional co activator called Yes associated protein 1 (Yap1). Yap1 is an effector of the hippo pathway and could cause cancer. Upon its interaction with Yap1, localization in the cytoplasm of the alpha catenin is enhanced. There is also nuclear localization in the alpha catenin null cells of the Yap1. In the human cancer cell tumors, there is a relationship between the abundance of alpha catenin and Yap1 activation. Therefore, alpha catenin inhibits the activity of Yap1. BAT-26 test This test is also referred to as Microsatellite instability and is used in detection of colorectal cancer. Colorectal cancers (CRC) that have an association with hereditary nonpolyposis colorectal cancer (HNPCC) have shown the presence of microsatellite instability (MSI). With MSI, changes in DNA cannot be repaired during DNA copying in the cell. This MSI can be detected in two ways, one being the use of BAT-26. Detection of MSI using BAT-26 allows for distinction of patients who have clinic-pathological characteristics that are same as those associated with HNPCC. BAT-26 is simple and less expensive, hence can be used in screening before analysis for mutation. BAT26 is stable in the MSI context, strongly suggesting that a large intragenic MSH2, a gene associated with HNPCC, has been deleted. CeMines CellCorrect Lab test This is a lab kit that has been developed by the CeMines Inc. It is used in diagnosis of lung cancer. The CeMines CellCorrect Lab kits are used to detect patterns of disease related antibodies in the blood stream. It uses a bio-informatics based analysis of statistics and an application for recognizing patterns. Cancer related antibody patterns are evaluated by this bio informatics application. The data is presented in a result sheet format that is easy to read and does not even require the interpretation of physicians. The Cemines’ test kit has shown increased ability to detect lung cancer at an early stage. Its validation is being finalized as studies are still underway. Chromosome 8q gain test Chromosome 8q gain test is used in management of prostate cancer. It is associated with early development in prostate cancer that is treated with hormones. From experiments done by Steiner et al, the primary core biopsies of metastasized prostate cancers have shown an acceleration in gain of 8q chromosome. Univariate analysis done indicated a relation between gain of 8q and progression in hormone treated cancer of the prostate. Aggressiveness in cancer of the prostate is therefore represented by gain in 8q chromosome. This can therefore be used to give an indication of the development of prostate cancer. SELDI-TOF-MS (Surface Enhanced Laser Desorption/Ionization-Time Of Flight-Mass Spectrometry) test It is also referred to as Molecular profiling using SELDI. Colorectal cancer does not have a good serum tumor marker hence its preoperative molecular stage is difficult to determine. SELDI-TOF-MS is a new way of seeking tumor markers. This involves a proteomics technology where a protein chip that is based on SELDI-TOF-MS bind the proteins that are in the samples unselectively. The combination of this SELDI-TOF-MS Protein chip technology and bio-informatics tools that are sophisticated helps in the discovery of new biomarkers. It also helps in the establishment of high sensitivity patterns which are used to differentiate the different stages in colorectal cancer. Melanoma inhibiting antigen (MAGE) test This test is used in detection of skin cancer. Hypoxia-Inducible factors (HIF) cause growth of new blood cells in tumors (angiogenesis) and glycolytic switch. Its activation can be regulated by low availability of oxygen. The HIF alpha proteins can be kept at low levels under the control of site specific hydroxylation that is done by prolyl hydroxylases (PHD). Usually the testis antigen of MAGE-11 interacts with the major HIF-alpha hydroxylating enzyme, PHD2. MAGE 11 is found to inhibit PHD activity without having an effect on protein levels. This inhibition is followed by the endogenous HIF-1 alpha protein being stabilized. Since MAGE 11 can inhibit the PHD and regulate activation of HIF, a regulatory mechanism for a novel tumor is developed. It is this that is utilized in skin cancer detection. Complexed Prostate Specific Antigen (cPSA) test Used in prediction and management of prostate cancer. It is advanced from the total PSA (tPSA) that is currently in use by many physicians. PSA is a glycoprotein that is produced by epithelial cells in the prostate. Serum PSA has been used to mark early indications of prostate cancer and to monitor progression of disease and effects of treatment in patients. However this has sometimes given false indications of cancer as the PSA levels could increase as a result of old age and not necessarily be cancerous. Majority of immunoreactive PSA in patients with cancer is complexed with alpha-1-antichymotrypsin. A cPSA assay from the Bayer Diagnostics was used in measuring PSA in complex with protease inhibitors. This assay is valuably used in eradication of CaP from benign prostate disease and also used to monitor CaP after primary treatment. This function is used in detection of prostate cancer and its subsequent management upon discovery. Cytokeratin 20 (CK20) test Cytokeratin 20 is a new histodiagnostic marker that is detected by monoclonal antibodies. CK 20 has been identified as a new cytokeratin polypeptide that can only be expressed in cells of the epithelial tissue layer, stomach cells, the oval receptor cells, and the intestinal lining cells. From experiments, CK 20’s expression in carcinomas was seen to resemble the one seen in the normal epithelia. Most of the adenocarcinomas of the stomach, ovarian tumors and oval receptor cells showed positivity in CK- 20. CK 20 is therefore a marker that can be used to establish various carcinoma types, especially as metastases. Cancer Antigen (CA 72-4) test The test is usually carried out using the CA 72-4 kit. It is majorly used in detecting gastric cancer and cancer of the ovary. Serum and plasma levels of CA 72-4 have been reported to be elevated in most malignant diseases. These include malignancies from epithelial tissues of the ovaries, pancreas and colon. Carcinomas of intestinal tracts and ovaries have shown high sensitivity during diagnosis. A good relation exists between the levels of CA 72-4 and the size of the tumor. For patients with gastrointestinal cancer, CA 72-4 is used in determining the type of therapy to be used for monitoring and any follow up care. When the marker of CA 72-4 indicates a high level, the patient in question risks a high chance of gastric cancer. eTag This method of testing is used in breast and lung cancer detection. In the development of many cancer types, receptor tyrosine kinases contribute majorly via their transmembrane. In the epidermal growth factor receptor, (EGFR), the epidermal growth factor and histidine rich glycoprotein, (HRG), attach themselves at the monomer extracellular regions and enhance dimerization of receptors. The activity of tyrosine is increased and the multiplication of cells cannot be controlled. eTag assays are used to determine the multiplication patterns of cancer cells. Only the tissues with ErbB/Her will indicate multiplication while the normal cells will indicate no multiplication from the eTag assays’ analysis of the patterns. Conclusion Since the invention of genetic testing, it has become easier to determine the risk one faces to any type of cancer. With this in mind, considerable control of the disease has been achieved. Some of the techniques developed are however expensive due to the technicalities involved in the testing. The efforts being made to convert all these techniques into a simple test kit such as that used in testing for pregnancy are highly encouraged. This would make it easier for most people to be able to know their status after the tests unlike in cases when one can’t afford to carry out the test and having to wait until the condition is severe before seeking attention of medics. References Charis Eng and Jan Viig, 1997, Genetic Testing: The problems and the promise,” Nature Biotechnology, Vol. 15, pp. 422-426. Chin et al, 2006, Genetic tests for cancer, Tufts-New England Medical Center, Washington. Issues in genetics, 2011, Overview Of Genetic Testing, retrieved on October 18th 2012 from . Steiner R.,2010, Anthroposophical Cancer Treatment, retrieved on October 18th from . Read More