Genetic alterations underlying the malignant transformation of cells. Besides, factors acting on the cells (food, chemicals, radiation, inherited mutations) the end point of all of them is the molecule of DNA that is damaged. For years, scientists are looking for key genes, mutations in which are crucial to the transformation of normal cells into cancer. Attempts to drug influence the results of these mutations create new branch in systematic drug treatment of tumors – target (target) therapy. The application of target drugs to tumor cells must be confirmed genetic changes that will ensure the response of the specific tumor specific and expensive treatment. The demonstration of key mutations is carried out in licensed genetic laboratories in the country after referral by a specialist in medical oncology.
Only in some localizations of cancer is necessary study of specific genes. For performing these studies provide patient in genetic laboratories paraffin blocks of material held bopsiya or surgery. They are kept in the hospital or center where intervention is performed and returned free of charge to the patient upon request and an identity document. Required in breast cancer is the study of the HER2 receptor status of tumor cells. This is done by a pathologist after biopsy or surgery by the so-called. immunohistochemical researches. Sometimes, this study does not give a definite answer about the amount of these receptors and confirmation is required genetic testing (CISH or SISH, which require special equipment and are available in 3-4 licensed places in the country). A positive result of the research determined the need for one-year use of targeted therapy with Herceptin in the absence of contraindications to it. It has been shown that even very small breast cancer with HER2 positive status pose a risk of recurrence of the disease, if not applied treatment with Herceptin, in parallel with chemotherapy.
Trastuzumab is a monoclonal antibody that is specifically directed to the HER2 receptor on tumor cells. Binding of the antibody to receptors prevent stimulation of cell growth factors and slows the division and spread of cancer cells. Treatment with Herceptin reimbursed by the State. One year of therapy with the drug is estimated at more than 70 thousand. Lev per patient and the application and required safe immunohistochemical and/or genetic confirmation of HER2 positive receptor status.
In routine practice are examined more RAS and EGFR mutation status, respectively in metastatic colon cancer and lung adenocarcinoma. Only certain genetic variants ensure sensitivity of tumors to specific targeted therapy with monoclonal antibodies and small molecule inhibitors. Some laboratories offer study of large sets of genes to demonstrate the sensitivity or lack of such schemes and to chemotherapeutic drugs. These studies have a high degree of evidence not introduced in the global oncology practice. Genes that are monitored are relevant to the application only targeted therapy that is different from the chemotherapy arm of systematic drug treatment in oncology.