Russian Scientists Have Found Out How To Predict The Results Of Preoperative Chemotherapy For Breast Cancer
Russian geneticists have developed a technique that uses the structure of three key genes to assess how effective preoperative chemotherapy will be for one of the most common forms of breast cancer, according to the press service of the Russian Science Foundation (RPF) with reference to an article in the journal Scientific Reports.
"Before prescribing preoperative chemotherapy, a tumor biopsy is performed. The same material can be used to analyze three markers of methylation (modification of the DNA molecule without changing the nucleotide sequence), which will provide additional information that can predict the sensitivity of the tumor to chemotherapy," said one of the authors of the study, head of the laboratory of the Medical and genetic research center (Moscow) Vladimir Strelnikov.
Breast cancer now ranks first in the number of tumors among women. It affects approximately 2.1 million women each year and claims the lives of about 627,000 of them. There are several different subspecies of breast cancer, they arise from different sets of mutations, and to combat them, different methods of chemotherapy are needed.
Strelnikov and his colleagues note that quite often doctors use chemotherapy before surgery. Sometimes this helps to reduce the size of the tumor and simplify surgical procedures. However, in about half of the cases, this therapy does not bring any effect. Scientists attribute this to the fact that doctors are not yet able to predict its effectiveness.
From theory to practice
Russian geneticists have solved this problem for one of the most common forms of such tumors – luminal B-subtype of breast cancer. It develops slightly differently than the most common type of such tumors – luminal-A. Until recently, doctors could not predict how preoperative chemotherapy would affect him.
A few years ago, Russian scientists discovered that the result of chemotherapy can be predicted fairly accurately by the number of epigenetic marks on the surface of several dozen key genes involved in the development of cancer. This technique worked well enough, but in clinical practice, it was almost impossible to apply it because of the great complexity and high cost.
Strelnikov and his colleagues found that fairly accurate diagnostic results can be achieved using only three genes from the set of DNA sites they discovered that are associated with the tumor's response to chemotherapy. They came to this conclusion by analyzing how epigenetic tags were distributed in the genomes of 25 breast cancer samples.
By comparing how often they occurred in different sets of genes, the scientists identified a set of three sections of DNA – IRF4, C1QL2, and DPYS. The level of methylation in them allows you to very accurately predict the result of preoperative chemotherapy. Moreover, such tests can be performed based only on the first two genes. The diagnostic accuracy reaches 75%.
Now Russian scientists are planning to conduct a broader test of this technique on large data sets that are available in leading cancer centers in Russia and the world. If their hypotheses are confirmed, this approach can significantly increase the effectiveness of chemotherapy in the coming years, the authors conclude.