Portrait of the aggressor
Scientists told what makes a cancerous tumor very aggressive
Tatiana Pichugina, RIA Novosti
The diagnosis of "cancer" is perceived as a death sentence, but nowadays this is not always the case. The most aggressive types of malignant neoplasms can be overcome if they are detected at an early stage or they are well controlled. The study of biological and genetic features of tumors allows scientists to talk about a personalized approach to the treatment of the "plague of the XXI century".
The earlier, the more effective
"There is no precise definition of aggressive cancer in medicine. This is what we call those types of tumors that do not respond well to treatment. At the same time, successful treatment has been found for some forms, but if it is not used, the disease quickly leads to the death of a person. There are tumors that can metastasize early and progress rapidly due to their biological characteristics. In the same organ, different people can develop tumors with different degrees of malignancy, therefore, individual treatment is selected," Alexander Petrovsky, Deputy Director for Scientific Work of the N. N. Blokhin Research Institute of Clinical and Experimental Radiology, Executive Director of the Association of Oncologists of Russia, tells RIA Novosti.
Petrovsky cites glioblastoma as an example – a brain tumor that is difficult to detect at an early stage. Screening studies for this type of cancer are not carried out because it is rare. The tumor affects an extremely important vital organ that cannot be completely removed or its essential part cut out. For this reason, surgical intervention is not always performed.
"Often these tumors, due to the peculiarities of their biology, spread through the tissue inside the brain. The complexity of early diagnosis leads to the fact that we mostly see them at common stages. We do not have an effective way of drug therapy for this pathology," the oncologist explains.
One of the most dangerous types of cancer are pancreatic tumors, because they are difficult to detect at an early stage and there are no effective treatments, and advanced lung cancer, which is difficult to control. Stomach and liver tumors are also poorly treatable.
On the contrary, a testicular tumor, even with brain metastases, can be completely cured, because there are effective methods for this. Such a case occurred with American cyclist Lance Armstrong, who was diagnosed with this type of cancer in 1996.
"Knowing the features of the tumor, we assume how it will behave, and plan appropriate treatment. In some cases, we do not treat prostate cancer at all. For example, if the patient has no symptoms, the disease is detected at an early stage, old age, and we understand that the tumor will develop very slowly, which most likely will not affect life expectancy. In another person of the same age, a tumor in the same organ may turn out to be aggressive, and treatment will be required," Petrovsky continues.
"Acute childhood leukemia is a very aggressive malignant disease. However, we, having effective drugs and bone marrow transplantation capabilities, successfully fight it in 90 percent of cases," Marina Sekacheva, Vice–rector for Research at Sechenov University, gives another example.
She explains that at an early stage, almost all types of cancer are treated well, unlike cancer processes at the metastatic stage. It also plays a role how successfully the patient's body fights the disease.
Personalized oncology and prevention
In Russia, tumors of the mammary glands, lungs, stomach, colorectal cancer, skin cancer are most often detected. The least aggressive types of skin cancer are basal cell and squamous cell, and there are very dangerous tumors, in particular melanomas. Ten years ago there were no ways to stop their development, now there has been a breakthrough in treatment. It is no coincidence that the 2018 Nobel Prize was awarded to American James Ellison, who developed immunotherapy initially specifically for melanoma.
Alexander Petrovsky notes that all cancer treatments are progressing: this is surgery, radiation therapy, which develops new energies, new types of therapeutic beams. At the same time, drug therapy is leading, where hundreds of new drugs for oncology have been developed in recent years. This became possible thanks to the study of cancer cells and the mechanism of their development.
"The best results in oncology can be achieved through prevention. In particular, quitting smoking significantly reduces the risk of many tumors, primarily lung cancer. Smokers account for almost 90 percent of cases of lung tumors in men. The fight against malnutrition, overweight can significantly reduce the risk of cancer. Physical activity at a certain level also helps to reduce the risk of malignant neoplasm and progression of the already identified and cured tumor," concludes Petrovsky.
Cancer genetics
The treatment of cancer patients is becoming more personalized, no wonder doctors say: how many patients – so many types of cancer. Artificial intelligence is required to analyze the entire array of patient data. Thus, the OncoTarget Center for Personalized Oncology at Sechenov University plans to create digital patient models with its help. First, the neural network is trained on large amounts of information, then full information about the patient is uploaded, including his genetic characteristics and tumors, clinical characteristics.
"Artificial intelligence will process the entire volume of data and will optimize treatment, calculate which of the forecasts is most likely," explains Marina Sekacheva, head of the Center.
The fight against cancer is impossible without genetic research. The better scientists understand the mechanism of tumor occurrence, the more effective treatment is being developed.
Unlike normal cells, which regularly die and are renewed, cancer cells are immortal. They divide indefinitely, covering the entire body with a tumor. What causes a normal cell to turn into a cancerous one, why a fatal mutation occurs in its DNA, is not yet completely clear. However, according to certain genetic characteristics, it is possible to assess the risks of how aggressively this or that tumor will behave.
"We study the genetic material of the tumor and identify markers. On this basis, we select drugs that can successfully fight this tumor cell. We are looking for a cure for a specific target. These are studies that are accessible to most patients, now they have been introduced into the CHI," says Marina Sekacheva.
Scientists can completely decode the DNA of cancer cells – sequencing. "Sequencing is used to develop new drugs, to better understand the biological characteristics of tumors, the genetic material of the person himself. It would be more convenient for doctors to do a full transcript than point studies in search of a specific marker. In fact, now we see one sentence from the book, if we mean by the book the entire DNA molecule of a tumor cell," says the oncologist.
In the coming years, sequencing will become much cheaper, registered devices will appear for a complete reading of the tumor genome, and then this method can be used in medical practice.
Marina Sekacheva clarifies that, including for this purpose, three genomic centers will be created in Russia as part of the national project "Science". Sechenov University is also organizing its own genomic center.
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