Introduction
Annotation
This article is devoted to the consideration of the prospects for the treatment of diseases of a carcinogenic nature through the use of various types of structures that fall under the definition of "nanorobots", including engineering and design solutions, as well as solutions implemented through molecular and cellular biotechnology. The article reveals the reasons why the use of such solutions is not widespread today, and also provides a brief forecast of the feasibility of these solutions in terms of the treatment of oncogenic diseases in the future.
Purpose: To consider the prospects of using nanorobots for the treatment of carcinogenic diseases;
Tasks:
1. Consider the concepts and types of engineering and biotechnological structures that fit the definition of "nanorobot";
2. To reveal the features of the selected solutions in terms of feasibility in the present and future;
3. Identify a number of the most suitable solutions for cancer therapy and substantiate their theoretical significance for the future.
Keywords: cancer, carcinogenesis, nanorobots, therapy, the future.

To date, oncogenic diseases are one of the most frightening phenomena for most people in the world. Thus, according to TASS materials, cancer is considered the most terrible disease by 69% of Russian residents [1] and approximately the same results have been recorded in other countries, for example, in the UK [2]. A particularly extreme form of fear of carcinogenic diseases has even received its own place in the textbook of psychiatry and the name "carcinophobia" or "carcinophobia".
At the same time, cancer is one of the diseases with the highest mortality rate and is among the TOP 3 causes of death from diseases, claiming the lives of about 10 million people annually [3]. 
Meanwhile, the very concept of "cancer" is a collective name for various types of malignant tumors and neoplasms with different etiologies, but a common symptomatic manifestation – these cells multiply and spread quite quickly, consume a large amount of organic substances of the body, originate from modified human cells and, with rare exceptions, are attacked by the natural human immune system, because They have a similar or identical genetic code, recognition sites and antigens on the cell surface, and a number of oncogenic cells use the forces of the immune system for their own nutrition [4].
In various science fiction films, nanobots or nanorobots come to help a person in the fight against carcinoma - microscopic robots that move freely through the bloodstream and in the interstitial fluid, they find a potentially dangerous object and attack it with the help of built–in devices. Meanwhile, whether such machines are possible at all is an open question, as well as whether they are capable of destroying cancer.
Let's start by defining what a nanorobot is and first highlight what the prefix nano means. Nano is a designation in the form of a prefix approved in the International SI System, denoting an object within the size range of 1× 10-9 degrees, or in other words, 1 billionth of something, in this case, 1 billionth of a centimeter. 
Based on the very definition of the nano prefix, we can already say that none of the potentially possible design mechanisms can fit the definition of a nanorobot, since objects such as DNA, RNA, proteins, antibodies or, for example, the smallest viruses are located within the size range of 10-9 degrees.
At this point in time, a person does not have such technologies that would be able to create a metal structure the size of a small organic substance, however, this is not required, because if we turn to the definition of a robot, we will get an exhaustive image of a nanorobot.
So, what is a robot? According to the International Federation of Robotics (IFR), "a robot is a working mechanism programmed along several axes with some degree of autonomy and capable of moving within a certain environment, performing assigned tasks" [5]. For convenience, we will break this concept into its component parts. And so, the robot must meet the following criteria:
1. It must be programmed by some creator;
2. It should be partially autonomous, that is, its algorithm of actions should have wide variability;
3. It must be adapted to move in a certain environment;
4. It must perform a certain function laid down by the creator.
Thus, we see that nanorobots have long been in the service of biotechnologists, geneticists and microbiologists – these are various kinds of genetically modified viruses, modified bacterial plasmids, wandering DNA elements or transposons, as well as sections of DNA, RNA, proteins, amino acids or, for example, lipids and polyglycosides with certain properties.
Viruses are most widely known as "controlled machines", because even the simplest of them are able to act according to a strictly defined algorithm. In nature, this algorithm is driven by the virus' thirst for self-replication by introducing its own genetic material into the host cell. Reprogrammed viruses, like natural ones, find proteins or glycolipid tips with a certain sequence of substances and charge on the cell membrane or membrane of the cell and use it to penetrate inside. Most often, viruses, by joining a specific antigen of a cell, initiate a pinocytosis reaction, that is, the mechanism by which the cell absorbs liquid food, however, there are a number of viruses that initiate phagocytosis – the mechanism of absorption of solids (mainly in unicellular animal organisms) or even are able to "push" their genetic apparatus through the molecules of the bilipid layer of cell membranes.
Then the virus uses various tricks to avoid being "eaten" by the cell, for example, it can disguise itself as nutrients migrating through the cell, it can disrupt the formation of the primary phagosome, disrupt the process of fusion of the digestive lysosome with the vesicle (phagosome) or even neutralize the digestive elements of the secondary lysosome (phagosomes fused with the primary lysosome). 
Eventually, the virus is embedded in the genetic apparatus of the host or "makes its own adjustments" to the process of reading (translation) of the matrix DNA by the ribosome. Here the paths of the real virus and the genetically modified one diverge. While a real natural virus triggers the process of destructive self–reproduction and multiplies uncontrollably, the programmed virus either does not replicate at all, embedding itself into the genetic apparatus of the cell forever, or replicates in limited quantities or strictly until a certain command is executed.
At the same time, artificial viruses have the same criterion of limited autonomy because they are able to recognize specific sequences of glycocalyx and cell membrane substances and infect a strictly defined type of cells, for example, selectively skin cells or cells of the immune system. However, there is a problem here, because most cancer cell lines do not have specific glycocalyx sequences that distinguish them from the surrounding tissue. For this reason, it is impossible to force the virus to selectively destroy a cancer cell, although, in some ways, there are exceptions. For example, according to an article by Robert A. Adair and his colleagues, they were able to identify and modify an oncolytic reovirus that selectively affects cancer cells and is practically harmless to other cells [6]. In addition, it is noteworthy that the virus causes an immune reaction of the body, which, hunting for the virus, triggers the process of apoptosis (self-destruction) also in oncogenic cells. Similarly, for example, the oncolytic function of a virus called CF33-HNIs is being investigated, which, according to the author, works against metastatic solid tumors [7].
Meanwhile, most viral drugs against oncogenic cells act in such a way that they alter or damage antigens on cancer cells or prevent them from secreting masking signaling proteins, opening up the human immune system to detect and destroy carcinoma. Meanwhile, here, in this variant, there are a number of disadvantages, for example, the same uncontrolled reproduction of the virus, which can occur when it mutates inside the cell or as a result of a violation of the storage conditions of the vaccine. In addition, the virus may not sufficiently change the antigenic sequence of the cell or be completely destroyed by the body's immune system even before it is introduced into all oncogenic cells.
Thus, we see some progress in the treatment of cancer with the help of biotechnological nanorobots, but many forms of malignant tumors still remain inaccessible for treatment in this way.
A number of studies also mention an alternative sensational method of treating a number of oncological diseases using plasmids (Extra-chromosomal DNA sites). With the help of a number of such plasmids, it is possible to modify the T cells of a patient with a cancerous tumor, the purpose of which is to increase the sensitivity of their own immune cells to cancer markers [8] [9] [10]. For example, one of the most well-known plasmids of this type are the plasmids phCMV-VHRhD-g1C-neo and phCMV-VLRhD-KR-ne [11]
Drugs using matrix RNA work similarly. They introduce it into T cells, which become more sensitive to oncogenic cells. For these purposes, for example, an RNA structure called mRNA-4157/V940 is used, which was created in a recombinant way and is currently being tested on patients by a team of researchers from the already well-known Covid-19 vaccine company Moderna [12].
Meanwhile, when talking about the future of cancer therapy using viral, plasmid or RNA therapy, one should not forget about the very origin of cancer cells in the human body. Cancer cells are the result of a mutation in ordinary cells of the body that occurs over a fairly long period of time. In order for a cell to become mutant and be capable of metastasis, among other things, it is necessary to accumulate more than one mutation in it, and for the medicine of the future such phenomena in cells will be unambiguously known even at early stages. Already today there are a number of methods for early diagnosis of cancer [13] [14] [15] and in the future this direction will only develop.
Conclusion
Thanks to the early diagnosis of cancer with the help of innovative techniques, genetic therapy will become possible, aimed rather at preventing the development of cells into neoplasms, as well as the formation of stable DNA combinations that prevent the occurrence of cancer.
Thus, I believe that nanorobots, despite their huge diversity and wide knowledge, even biotechnological ones, are only an intermediate link between the total victory over cancer diseases all over the world and in the next 50 years, the prevention of cancer diseases can forever save humanity not only from cancer, but also from the need for new methods for his treatment.