Clinical FeaturesOncology

Why does cancer occur and is it possible to avoid its development?

“Not every cause which reaches the body has an effect on it and no disease can be caused without a corresponding susceptibility of the organism.”


Written by Tatiana Iarmak –
Lecturer of the Department of Advanced Training of Junior Medical Specialists at the Municipal Health Care Institution ‘Kharkiv Regional Medical Vocational College’, Kharkiv, Ukraine. An independent trainer, consultant to medical facilities and non-medical facilities to instruct medical staff on how to safely provide services to patients/clients. Corresponding Author details:

Key words

Cancer, tumors, malignant tumors, viruses, viral infections, bacteria, bacterial infections, cancer theories, parasitic infections; risk factors; lifestyle; stress; antibiotics; immunity, prevention.

The aim of the study:

Show the relevance of the problem of oncological diseases, the influence of age, lifestyle; heredity; viruses, bacteria, helminths; risk factors; state of the immune system of the human body; the importance of prevention and immunoprophylaxis, early diagnosis in preventing the occurrence and the development of the malignant tumors.

Brief summary:

This article examines the dependence of the incidence of cancer of various origins on the lifestyle, age, heredity; the presence of chronic infectious diseases in humans; risk factors, the state of the immune system.


Ancient medicine left a huge legacy to the modern medicine, which has been using very actively the relevant today knowledge of ancient Greek, ancient Roman and other physicians, philosophers, and scientists. The tumors have been known for a very long time. Information about them was first obtained from the ancient Egyptian manuscripts “Papyrus of Edwin Smith” and “Papyrus of Ebers” (1600 BC). In ancient Egypt, not only bodies, but also individual organs of dead people were mummified – during mummification, the malignant formations are preserved much better than healthy tissues, thanks to that, modern scientists have information about the ancient Egyptians, who had cancer of various localizations more than 4000 years ago. With the help of modern technologies, such as computed tomography (CT) and others, the scientists can discover the traces of tumors in ancient mummies. The scientists all over the world have been studying tumors for many years. Michael Zimmerman, paleopathologist, professor at Villanova University (USA) and at the KNH Center for Biomedical Egyptology at the University of Manchester, for the first time histologically verified the diagnosis of the colorectal cancer, while studying the mummy of an ancient Egyptian. The traces of a tumor – a fibrous dysplasia in the rib of a Neanderthal man, who lived about 120 thousand years ago, was discovered in Croatia more than 100 years ago, and only today this find has attracted the attention of the scientists from the University of Pennsylvania (USA) and is considered to be the oldest archaeological find. Dr. Kat Arney – a British writer and scientist, who took part in the study of the remains of the Neanderthal, in her book “Rebel Cell: Cancer, evolution and the science of life” (2020) talks about the role of cancer in human life and how it can be stopped. Ann Rosalie David – a British egyptologist and emeritus professor at the University of Manchester with Michael R. Zimmerman in her book “Cancer: an old disease, a new disease or something in between?” (2010) talks about the role of the environmental carcinogens in the occurrence of tumors, the need for a deeper study of their etiology and pathogenesis, and the development of the effective prevention methods.

The “father of medicine”, Hippocrates, in his work “Carcinoma” for the first time called the tumor “karkinos” (cancer or crab), since it looks like these crustacean animals. Hippocrates gave a description to many types of cancer: skin, nasopharynx, breast, rectum, etc. He also introduced the term “onkos”, oncology was named from – a science, which studies the causes of tumors, the mechanisms of their development, the clinical course and develops the diagnostic methods, treatment and prevention. Aulus Cornelius Celsus – an ancient Roman physician, translated the Greek word καρκίνος into Latin сancer – this term is used in modern medicine today. Hippocrates and Celsus considered the main method of treatment to be the surgical removal of the external tumors, however, operations were not recommended for the internal tumors, because in ancient times, complex operations were more lethal than the tumor itself. In the medical treatises of ancient India, China, Babylon, there are also references to malignant neoplasms. Swiss physician, alchemist, philosopher of the Renaissance, one of the founders of iatrochemistry (the direction of alchemy of the 16th-17th centuries for the preparation of chemical drugs), Paracelsus, described the miners’ disease “Schneeberg lung disease” or “Schneeberg miners’ disease”, which main cause was a constant inhalation of the ore dust rocks, containing the radioactive substances, in particular, radon and its decay products in the stagnant air of mines. This lung disease was later identified as the lung cancer. An English surgeon Percivall Pott proved in 1775 that chemicals can be carcinogens, i.e. cause the development of malignant tumors. He described the scrotum cancer in chimney sweepers, caused by the soot from chimneys, and called it the “chimney sweep cancer”. Chimney sweepers themselves called this disease the “soot wart.” The world’s first law to protect a person from carcinogens in the workplace was passed on July 5, 1788.

Until the 19th century, the oncological diseases were recorded quite rarely. An incredible growth of the oncopathology has arisen, particularly, in the last two decades, which is more associated with the various bad habits (smoking, drinking alcohol, unhealthy diet, etc.), polluted ecology, and an increase in the human life expectancy. Cancer is the second leading cause of death in the world after cardiovascular diseases, but the upward trend in oncological diseases may soon put it in a leading position. The variety of species, types, and forms of malignant tumors is causing an increasing concern among specialists. The cause, the mechanism of the occurrence, the origin of the malignant tumors are not fully understood. A number of outstanding scientists have created many theories of the emergence and the development of tumors. German scientist of the second half of the 19th century, Rudolf Virchow, is the founder of a cellular pathology, a creator of the theory of irritation, in other words, a the theory of the onset of tumors, according to which, a frequent irritation or trauma of the tissues of the human body (stomach, rectum, cervix, and other organs) accelerates the processes of the cell division and can cause their malignant growth. In 1911, Francis Peyton Rous, an American pathologist, Nobel laureate for his discovery of tumor-inducing viruses (1966) proved that a malignant tumor of chickens (Rous sarcoma) can be transmitted from a sick bird to a healthy one by the acellular filtrates – viruses, which are the etiological factor in the origin of tumors. The viral theory of cancer had been making its way for many years. Rous received the prize only 55 years after his discovery. Many scientists over time have confirmed the viral and infectious nature of cancer, i.e. an ability to be transmitted from person to person. The theory has more than 110 years of history. 20% of all tumors in the world are caused by viruses.

Currently, the viruses which cause tumors in humans include:

  1. Epstein-Barr virus (EBV) or human herpes virus type 4 (HHV4) – the first isolated virus, which causes Burkitt’s lymphoma (1964), nasopharyngeal cancer (carcinoma), stomach cancer, and many diseases of infectious (infectious mononucleosis, etc.) and of non-infectious nature. EBV is one of the most common viruses among the world’s population (latent carriage – 95%) – human papilloma virus. Today, more than 100 types of HPV are known.
  2. Harald zur Hausen, a German scientist, isolated the first oncogenic human papillomavirus (HPV) type 16 in 1983 and in 1984 – HPV type 18. It is these two types of HPV that cause 70% of cases of anogenital cancer in men and women. In 2008, Hausen received the Nobel Prize for his discovery of the human papillomavirus as the cause of cervical cancer. HPV is most commonly transmitted sexually (80%); a possible infection of the fetus from the mother during childbirth, through microtrauma of the mucous membrane of different localization (larynx, pharynx, etc.) and skin. A latent carriage under the adverse conditions can turn into cancerous tumors within 15-20 years. The first HPV vaccine was introduced in 2006 (developed by Australian scientist Ian Frazer and Chinese scientist Zhou Jian), which protects against the development of the cervical cancer. In 2019, Ian Frazer and Chinese scientists at the Xiamen University started to develop a new vaccine, which will help stop the development of cancer in people who already have it.
  3. hepatitis B virus (HBV) was discovered in 1963 by Baruch Blumberg, an American scientist, who received the Nobel Prize for this discovery in 1976. Hepatitis B is transmitted parenterally – through medical instruments or materials infected with blood or biological fluids (during manipulations, operations, dental procedures); damaged skin and mucous membranes (piercing, tattoo, manicure, pedicure), intravenous drug injections; sexually, from mother to fetus during childbirth, with breast milk; kisses (saliva), transplantation (transplantation of organs and tissues), by fomite transmission (personal hygiene items-toothbrush, shaving razor, scissors). In 5% of the patients with chronic hepatitis B, the primary liver cancer develops and is more often recorded in men, suffering from cirrhosis of the liver (20%). Maurice Hilleman – an American vaccinologist developed the first plasma vaccine in 1981. Subsequently, the vaccine has been improved many times. Vaccination against hepatitis B is included in the vaccination calendar in all countries of Europe and America. Thanks to the vaccine, the incidence of hepatitis B has decreased by 80%-90%.
  4. hepatitis D virus (HDV) – discovered by an award-winning Italian virologist Mario Rizzetto in 1977 in patients with hepatitis B. Hepatitis D develops only in the presence of the hepatitis B virus in the human body and provokes the occurrence of the hepatocellular carcinoma (the primary cancer). Transmission routes are identical to hepatitis В. The hepatitis B vaccine protects against the hepatitis D infection.
  5. hepatitis C virus (HCV) was discovered in 1989 by American scientists Harvey J. Alter, Michael Houghton and Charles M. Rice, who jointly became Nobel Prize winners for their discovery of the Hepatitis C virus in 2020. The hepatitis C is called an “affectionate killer”, because it can be latent in the human body for many years. Chronic hepatitis C can cause cirrhosis of the liver and a hepatocellular carcinoma (primary liver cancer). The routes of transmission are identical to the hepatitis B. The vaccine has not been developed yet.
  6. human T-lymphotropic virus (HTLV-1) – an oncogenic retrovirus – the causative agent T-cell lymphoma mostly in adults and a HTLV-1-associated myelopathy (tropical spastic paraparesis). The routes of transmission are identical to the hepatitis B and C. Lifelong carriage.
  7. herpes virus HHV-8, associated with the Kaposi’s sarcoma was discovered in 1994 by an American virologist, professor of the American Cancer Society, Yuan Chang. She received numerous awards for her cancer researches. The transmission routes of HHV-8 are identical to those of the hepatitis B, C, human T-lymphotropic viruses. In addition to blood, the saliva poses a serious danger. Crowded living, non-compliance with the sanitary and hygienic rules can lead to early infection in childhood.
  8. Merkel cell polyomavirus provokes Merkel’s sarcoma – an aggressive form of the skin cancer, more common in the elderly and immunocompromised people; was identified by Yuan Chang in 2008.
  9. A virus, which causes severe complications in patients with glioblastoma (a brain tumor is one of the most lethal types of human cancer) is Cytomegalovirus (CMV); it belongs to the Herpesviridae type 5 family (HHV-5). CMV was first discovered by the German pathologist Hugo Ribbert in 1881 and isolated in 1956 by American scientists Thomas Huckle Weller, M. Smith and Wallace P. Rowe. CMV does not cause cancer, but it can accelerate the development, complicate the course of an existing disease and lead to death due to the reactivation (studies by Chang-Hyuk Kwon, Ohio State University Comprehensive Cancer Center). The infection occurs similarly to the hepatitis B, C, D, and also transplacentally (penetrates the blood-placental barrier) at any stage of pregnancy, provoking the occurrence of the intrauterine infections. The virus is contained in almost all human biological fluids: blood, semen, vaginal secretions, saliva, tears, etc. and persists for life in the human body (the latent carriage from 60% to 90% of the world population). All the viral infections which provoke the development of cancer are the infections, associated with the provision of medical care (hospital infections), and often occur in medical institutions when the anti-epidemic and sanitary and hygienic regimens are not observed. They are also included in the list of absolute contradictions for donating blood.

Helicobacter pylori (H. Pylori) is a causative agent of the intestinal bacterial infection, discovered in 1979 by Australian scientists John Robin Warren and Barry James Marshall. For this discovery they received the Nobel Prize in 2005. H. pylori is registered in all countries of the world. In developed countries, the level of latent carriage of H. pylori is 15-30%, in developing countries – 50-70%. In 1994, the International Agency for Research on Cancer (IARC) recognized the H. pylori infection as the first-order carcinogen, which means that H. pylori has an unconditional link with the occurrence of the stomach cancer. H. pylori lives in the stomach, provokes the development of gastritis, gastric and duodenal ulcers,   leading to cancer. Non-observance of the sanitary and hygienic rules plays an negative role in the transmission of infection, so the main route of transmission is fomite transmission, in other words, by touching the contaminated household objects. The transmission factors are dirty hands, other people’s dishes (cups, spoons, etc.), even kisses. It is also possible to become infected with H. pylori during the passage of an endoscopic examination – fibrogastroscopy, because of a poor-quality disinfection and sterilization of a fibrogastroscope. Also, in the formation of oncogenesis a serious threat is posed by the parasitic diseases (helminthiases) – a class of trematodes: a. Schistosoma haematobium causes squamous cell carcinoma of the bladder. Infection is possible through a contact with water, polluted with the helminth eggs (bathing, fishing). b. Clonorchis sinensis provokes the gallbladder cancer (cholangiocarcinoma). c. Opisthorchis Viverrini causes liver cancer, hepatocellular carcinoma and pancreatic cancer. Clonorchiasis and opisthorchiasis can be contracted by eating raw, lightly salted or undercooked freshwater fish. In case of opisthorchiasis, the infection occurs more often by the fish which is part of the carp family. These types of helminthiases are included in the IARC list of carcinogens.

In 1965, by the decision of the World Health Assembly (WHA), the International Agency for Research on Cancer (IARC) was established as an independent structure of WHO. IARC has coordinated the international researches of the causes of cancer in humans, has studied the mechanisms of carcinogenesis, and has developed the cancer prevention strategies, especially in low- and middle-income regions. The results of the IARC researches have served as the basis for the development of the cancer prevention and control programs. The IARC list includes 116 names of carcinogens (from the Latin “cancer” – cancer and ancient Greek “γεννάω” – I give birth), i.e. substances which contribute to the development of cancer. They are divided into: a. chemical: benzene is part of gasoline, plastics, dyes, rubber, some drugs; dioxins are formed during the burning of the household waste; tobacco products; food additives – E 121, E 123, etc., prohibited by law  (WHO, UN organizations – Food and Agriculture Organization – FAO); ethanol in alcoholic beverages, etc.; b. physical: ionizing and ultraviolet radiation; c. biological: viruses, bacteria, helminthiases (84% – WHO data).

Chronic infections, malnutrition, stress upset the balance of the human body and lead to a decrease in immunity and can cause the development of cancer. According to the immunological theory, when the function of the immune system is impaired, the cancer cells “escape” without being recognized by the immune system, which leads to the appearance of neoplasms. In 2018, James P. Allison, an American immunologist and a Japanese scientist Tasuku Honjo received the Nobel Prize for their discovery of the anti-cancer therapy by suppressing the negative immune regulation. Thanks to their discovery, the drugs for tumor immunotherapy have been created in recent years, which can slow down the process of the tumor development even at the fourth stage. Even Hippocrates spoke about the psychological factors that affect health and provoke the development of tumors and recommended “to beware of the emotional unrest …”. An ancient Roman physician and philosopher Galen suggested, that the temperament affects the development of tumors: melancholic people get cancer more often than the sanguine people. The psychosomatic theory of cancer is directly related to stress. Stress (tension, pressure) is the reaction of the human body in response to various kinds of stimuli – stressors, as negative (distress) associated with the long-term experiences – trauma, loss of a loved one, conflicts in the family, at work; abrupt changes in lifestyle – retirement, frequent relocations, emigration, war, etc., and positive (eustress) nature – marriage, childbirth, admission to the University, etc.  Most adults and elderly cancer patients do not want to talk about their problems, but carry them in themselves, thereby, aggravating the disease, while many children, adolescents, young people with cancer actively use the concept of “oncological coming out” (“disclosure”, “exit”) – they share their experiences on social media; participate in forums, talk shows; seek help, emotional and financial support. On the contrary, adults and elderly people are mostly not ready to open up, share, and some do not own or do not have modern gadgets. A Canadian scientist, the founder of the doctrine of stress, Hans Selye, in 1936 published his first work “Syndrome caused by various damaging agents”, in which he used the term “general adaptation syndrome” (from Latin “adaptare” – to adapt, Greek “syndrome” – combination). Stress plays a huge role in everyone’s life. It can be acute, which ends quickly and chronic or permanent, debilitating, leading to poor health, depression (often a person feels very lonely, unwanted) and the possible occurrence of cancer. Stress releases the stress hormones adrenaline, norepinephrine, and cortisol. The researches by scientists from the United States and Germany have shown that after a few years of recovery from cancer, the immune cells (neutrophils) and the increased levels of the hormones norepinephrine and cortisol can contribute to the recurrence of tumors, which leads to death, as well as to the development of oncology at an early age. Most types of cancer are genetically determined, but not all and not always are inherited. There are many more theories, however, in recent years, scientists have come to a conclusion that the development of cancer comes from the influence of many risk factors, the factors potentially dangerous to human health, contributing to the occurrence of diseases, in particular, the malignant tumors. These include: the use of tobacco, alcohol; chronic infections; abortions and childbirth of the first child after 35 years; living near power lines; lack of physical activity, malnutrition – fast food, high-calorie, fatty, spicy foods, lack or few vegetable and fruit in the diet; obesity or overweight; negative emotional state; stress and nervous strain; polluted ecology and more (WHO data). The polyetiological theory of cancer – when the carcinogenic factors (chemical physical, biological), infectious, parasitic, fungal diseases; the state of the immune, neurohumoral systems of the human body; genetic predisposition, risk factors (smoking, alcohol, etc.), polluted environment, contribute to the emergence and the development of cancer.

Cancer is a global problem. Cancer affects all the organs and tissues of a person. 19.3 million people worldwide developed cancer in 2020, out of which 10 million died. The number of cancer cases by 2040 will be 47% higher than in 2020. Every 5th inhabitant on Earth gets cancer, every 8th man and 11th woman die. 70% of all deaths occur in countries with low and middle living standards (WHO data). The most commonly diagnosed cancers are breast, lung, colon, rectum, prostate and stomach ones. One of the most common cancers in Ireland is bowel cancer which kills about 1,000 people every year. Most patients are unaware of the disease, because in the early stages there are no manifestations. The incidence of cancer increases with age. However, in recent years, 400,000 children have been diagnosed with cancer every year, which has become one of the main causes of death among children and adolescents. In 2050, 27 million new cases of cancer and 17.5 million deaths are being forecast (International Union Against Cancer, UICC). On February 4, 2021, the WHO Regional Office for Europe (WHO/Europe) launched an initiative “United Action against Cancer” – from prevention and early detection to diagnosis, treatment and palliative care. In the framework of this initiative, the innovative approaches to the fight against cancer are being developed. The long-term goal is “the elimination of cancer as a life-threatening disease in the European Region”. Since February 4, 2005, the World Cancer Day has been celebrated annually under the auspices of the International Union Against Cancer, UICC in order to draw the attention of the world governments and public organizations to the problem of cancer. The World Cancer Day in 2022-2024 has been dedicated to the theme – “Everyone deserves access to cancer care”. Every year the World Breast Cancer Day is celebrated in October and the World Pancreatic Cancer Day (initiated by WHO) in November. On November 17, 2021, the WHO launched a historic movement, bringing together the global community to eliminate the cervical cancer for the first time and unveiled the Global Strategy to Accelerate the Elimination of the Cervical Cancer as a Public Health Issue. The resolution was adopted by 194 countries. In December 2022, WHO presented data on the resistance of the bacterial infections to the antimicrobial drugs (AMR) – more than 50% are resistant. Bacterial infections are common complications of cancer that must be treated with antibiotics. AMR will slow the progress in cancer prevention and treatment for many years. “Antimicrobial resistance undermines the modern medicine and endangers the lives of millions of people,” WHO Director-General Tedros Adhanom Ghebreyesus said in the report. The tumors of breast and cervix are women’s health and every woman has the right to be healthy. According to WHO, the mortality from cervical cancer will increase by 22% by 2030. As a way to draw attention to the problem, many types of malignant tumors are distinguished by different colors of the symbolic ribbon. For example, a lavender ribbon means cancer of all types, pink – breast, turquoise – cervix, purple – pancreas.

The basis of the fight against oncological diseases is prevention, which prioritizes a healthy lifestyle, as it provides each person with individual health, well-being and longevity. For that, it is necessary a proper nutrition – more vegetables, fruits and berries in the diet, eating low-calorie foods – cereals (buckwheat, rice, etc.), beans; physical activity (running, exercise, etc.), walking in the fresh air; positive emotions; UV protection; giving up bad habits – smoking, alcohol, drugs; prevention of the infectious diseases (viral, bacterial, parasitic, fungal); vaccination against hepatitis B and human papillomavirus, since other vaccines against carcinogenic viruses have not yet been developed; strengthening of the immune system, in particular, by the intake of vitamins C, group B; A, E, etc.; minerals – magnesium, zinc, potassium, calcium, etc.; antioxidants – selenium, etc.; early diagnosis. Unfortunately, it is impossible to completely avoid the effect of carcinogens on the human body. They are everywhere: at home – household chemicals, microwave ovens, furniture and harmful wood materials (chipboard, fiberboard, MDF), plastic, replacing the harmless natural wood; at work – when professional activity is associated with the hazardous production, such as chemical production – the manufacture of medicinal, disinfectant preparations, varnishes, paints, etc., building materials, food, glass, and others; in the environment – radiation, vehicle exhaust gases, soil, water, etc. The scientists in many countries have been conducting thousands of studies to reduce the risk of the development of tumors, to prevent metastases,  to create a cure, a cancer vaccine and enable humanity to live without cancer. Ukrainian scientists headed by V. Litvinov, the director of the Antarctic Center (NANC) at the polar station “Akademik Vernadsky” in Antarctica, have created a cure for skin cancer (melanoma – one of the most aggressive forms of malignant tumors in humans) based on the herbaceous plant meadow grass – it tolerates low temperatures (- 40°C), ultraviolet irradiation, has anti-melanoma, antiviral, anti-inflammatory, antibacterial action. The medicine made from the meadow grass was called “Melovit”. Currently, the drug is being tested at the Educational and Scientific Center “Institute of Biology and Medicine” of the Kyiv National University. Taras Shevchenko. Professor of Cellular Dermatology and Oncology – Penny Lovat and the scientists at Newcastle University created the “AMBLor” test to detect melanoma. The test is applied to a biopsy after the removal of the primary melanoma and reveals the individual level of a possible cancer recurrence (low, high) in each patient. The research is still ongoing. The scientists from the Australian Edith Cowan University (ECU) have developed a test for the early diagnosis of melanoma, which will detect the specific antibodies formed already in the very early stages of melanoma, which will reduce mortality and save the lives of millions of people. The test is at the stage of clinical trials.


Cancer is a global problem in all countries of the world. Every year, millions of people fall ill with various types of cancer and about half of them die. Healthy lifestyle, preventive measures, early diagnosis, identification and elimination of the risk factors, new methods of diagnostics and treatment, programs of the WHO and other organizations involved in the problem of cancer, will make it possible to reduce the risks of the occurrence and the development of tumors, reduce the death rate from cancer and even prevent it.

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