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Genes and Breast Tumors The development of all tumors originates in a multi-stage process of genetic material defects (so-called mutations) accumulating in the nucleus, which ultimately leads to transforming a previously healthy cell into a cancerous one. In the case of a genetic susceptibility to tumors, a patient inherits, from one of the parents, a defective copy of a gene, or genes, responsible for the correct functioning of genetic material repair processes or for controlling correct cell divisions. Having a damaged gene thus increases the risk of developing cancer. However, and this ought to be clearly emphasized, it does not predetermine the actual occurrence of the disease, since that would require for the patient to also be exposed to factors damaging the organism’s cells’ genetic information. It is estimated that approximately 10%-20% of breast and ovarian cancer cases occur in women who carry a mutation in the BRCA1 or BRCA2 genes. In other female patients, the attempts at identifying the genetic alteration contributing to a tumor’s development have been unsuccessful, despite a sometimes evident familial burden (numerous family members suffering from breast and/or ovarian cancer, occurrences at a very young age). This results from the fact that the genetic tests which are currently available enable the identification of only chosen genetic alterations responsible for an increased susceptibility to developing cancer, while others still remain undiscovered (undetermined) or the methods allowing their identification are simply too costly. That is why, when determining whether a patient and her family members qualify as belonging to the group of high breast and/or ovarian cancer incidence, apart from carrying out genetic tests, a thoroughly conducted interview concerning first-degree family members (parents, siblings, children) as well as second-degree relatives (grandparents, grandchildren, mother and father’s siblings) is of fundamental importance. When analyzing genealogy, a medical geneticist pays special attention to the incidence and type of tumors as well as the age of onset. A thorough genealogical analysis makes it possible to determine whether genetic tests ought to be recommended, to identify the scope of the tests and, sometimes, a preliminary qualification of a patient to the high-risk group. It is also advisory for the patients to collect the genetic results directly from a medical geneticist along with a proper interpretation as well as a personalized list of recommendations concerning preventive testing. Any other person wanting to determine their carrier status for a mutation which would increase the risk of developing cancer may, of course, have a genetic test performed. It is worth selecting a test which enables identifying both common and rare mutations, at a reasonable cost, and inquiring about the sensitivity of the identification method used – tests based on genetic material sequencing being the most sensitive (sensitivity>99.9%). In all cases, it is recommended to visit a genetic counseling office in order to consult the results and receive comprehensive genetic advice. Families which qualify as belonging to the high-risk group are those in which:
Recommendations for women from families at a high risk of developing breast and/or ovarian cancer (based on the recommendations issued by the European Society for Medical Oncology (ESMO 2011))
ATTENTION: In every case of an identified mutation in the BRCA1 or BRCA2 genes, it is necessary that the patient obtains counseling from a physician specializing in clinical diagnostics so as to be presented with personalized options of active prevention. Anna Poluha, Doctor of Medicine Expert on Clinical Genetics GENOMED Genetic Counseling Office ul. Tomasza Zana 29/XIX, Lublin |