Molecular diagnostics is more and more often used to diagnose the causes of many diseases. Regardless of whether our he alth problems are related to metabolic diseases, cancer or failure to enlarge the family, their causes are increasingly being looked for in the genetic material. What is such research about?
Molecular diagnostics( genetic testing ) increases the effectiveness of treatment and the chances of survival. In order to identify genetic abnormalities in the human body, cell chromosomes can be examined. This is what cytogenetics does. Molecular biology methods are used to evaluate gene structures by analyzing the composition of the genetic information carrier, i.e. DNA (sometimes also RNA). The practical effect of knowledge in the field of genetic foundations of neoplasm was the development of new therapies - incl. molecularly targeted drugs. In other words, the drug destroys cancer cells with a specific genetic disorder, that is, DNA that is damaged in a certain way. Such therapy, called targeted therapy, is usually more effective and less toxic than classic chemotherapy.
It is the personalization of treatment that requires a genetic test before starting treatment. A correctly performed genetic test will indicate patients who have a chance to benefit from the selected targeted therapy, and those in whom the molecular type of cancer precludes the effective action of the same drug.
Molecular diagnostics: how is it done?
To make the diagnosis accurately, the diagnostic method must be adapted to the parameter we want to evaluate. The procedure is different to determine the presence of a known mutation, and the procedure is different to look for an unknown disorder in a gene suspected of having a malfunction. The method used must also be selected according to the biological material to be tested. Acquired genetic disorders, responsible for the formation of 80-90% of cancers, can only be detected in malignant cells. Therefore, the study is performed by analyzing the material obtained from the tumor cells. Tumor tissue obtained during surgery or biopsy is brought to the laboratory. This is the case for mostsolid tumors. If we are dealing with leukemia - the appropriate material for the analysis of genetic disorders are bone marrow cells, which are collected under local anesthesia by the method of trepanobiopsy (excision of a bone fragment along with the marrow) or aspiration biopsy (suction of material for examination). In tests aimed at assessing cancer susceptibility, it is enough to take blood from the patient. This is done in the same way as for morphology.
Predisposition assessment
In the case of many familial cancers, it is known which genes, or rather their abnormal (mutated) forms, increase the risk of the disease. The presence of such a predisposition in a he althy person is a warning signal, prompting more careful he alth control, and in special situations - to use specific preventive methods. It also turns out that in the case of some hereditary neoplasms, the course of the disease and the effectiveness of treatment will be different compared to the same type of cancer, but occasional, i.e. not related to damage to the predisposition gene.
On the trail of mutant cells
Genetic cancer research currently accounts for about half of all genetic research carried out. They are performed for three main purposes. The first is the diagnosis of the disease and the exact classification of the neoplasm. The second - the precise selection of the treatment method. The third is the assessment of the inherited predisposition to develop cancer.
Until recently, tumors were classified according to the course of the disease (clinical evaluation) and the examination of cells under a microscope (cytology) or the tissue of the removed tumor (histopathology). Thanks to the advances in knowledge about the biological mechanisms of cancer formation and development, we know that "similar-looking" neoplasms can significantly differ in prognosis, for example. There may be genetic differences between such cancers, which often determines the choice of treatment. Currently, many leukemias, lymphomas and solid tumors cannot be clearly classified without the help of genetic testing.
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The costs of genetic testing vary significantly depending on the method used, the scope of the test, the analyzed gene or the number of necessary procedures. That is why they can range from several hundred to several thousand zlotys. Unfortunately, in Poland genetic tests are not reimbursed in all cases. Meanwhile, in many cases, carrying out genetic tests would allow for well-selected and economical management of expensive anti-cancer therapies orearly detection of tumors. Free access to a specific genetic test depends on many factors, including on the type of targeted treatment proposed, i.e. whether it is used as part of a drug program, whether clinical trials are conducted in the hospital, and also the financial condition of a specific oncology center. In the case of a diagnosed cancer, the decision to undertake a genetic test and its direction is made by a pathologist (to establish the diagnosis) or a clinician (for the selection of targeted therapy). However, it should be remembered that molecular diagnostics does not replace, but complements other tests, e.g. imaging (ultrasound, mammography, X-ray), histopathology and others.
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