Previously, the discovery of geneticists had no practical application in clinical medicine, but in recent years, genetics has made a huge leap. First of all, we are talking about the treatment of oncological diseases, but not only them. For example, now doctors have the opportunity to find a cancer patient specific to cancer cells genetic changes and influence them pointwise – this is called targeting therapy or biological treatment. It is also possible to determine whether the patient has a mutation, which can be the basis for positive prognosis in immunotherapy. Accordingly, doctors today pre-select medicines that are likely to help the patient in his specific case. Another example – treatment of breast cancer, the most common cancer in women and the second most common after lung cancer in general. Until recently, all women with breast cancer, in the early stages, when there is no metastasis yet, received surgical, hormonal (in hormone positive cases) treatment and chemotherapy. In developed countries about ten years ago, it became possible to conduct genetic studies to determine the need for and, most importantly, the usefulness of chemotherapy for a particular woman who is ill. It is unequivocally proved that 70% of patients with estrogen-positive tumors were enough surgical treatment and hormonotherapy, they did not need chemotherapy.
Unfortunately, in the former USSR countries, genetic testing of hormone-dependent breast cancer has not yet become a standard, even in the most expensive and prestigious clinics.
Ordinary chemotherapy has a systemic effect on the entire human body, destroying both cancer and healthy cells. It is both dangerous and very difficult to tolerate by patients. In the last decade, new drugs of biological and immunotherapy have been introduced into clinical practice, acting on different principles:
Biological drugs work point by point, destroying only genetically modified cells and not affecting healthy cells. For example, Zelboraf blocks serine threonine kinase, which is encoded with the BRAF gene, and the latter in turn is responsible for melanoma development. The patient undergoes genetic testing and if the BRAF mutation is confirmed, Zelboraf becomes a salvation. Immunotherapeutic drugs train and mobilize the human immune system to fight against cancer cells. A cancer tumor is an out of control group of cells with DNA failure, which manages to disguise itself and become invisible to the immune system. Immunological drugs, to put it simplistically, remove the disguise from the cancer formations, giving the command “face” to the immune system, after which it destroys the tumor throughout the body, including the removed metastases, without harming healthy cells. In recent years, methods have also emerged that allow the laboratory to test the effects of different types of chemotherapy, immune and biological therapy on a specific tumor tissue of a particular patient. Doctors take a sample of tissue from a patient by biopsy, the resulting drug in the laboratory is divided into parts, to each apply different methods of treatment and monitor the reaction of cancer cells. Thus, specialists have a high probability to determine in advance what kind of treatment will help a particular patient more and less. And this is a huge breakthrough in medicine: the patient will not spend a huge amount of money and, most importantly, precious time on “roulette playing”, trying different methods of therapy at random.