Four microorganisms contribute to the development of most infectious tumors
Three types of virus (hepatitis B and C virus, papillomavirus) and a bacterium (Helicobacter pylori) contribute to the development of most tumors of infectious origin.
Currently, there is no doubt that certain pathogenic microorganisms that cause infectious diseases in humans are important risk factors for the development of a number of oncological diseases. During the study, the authors analyzed the pathogens of infectious diseases classified by the International Center for Research on Cancer (Lyon, France) as carcinogenic to humans. The research group estimated the prevalence in the oncopathology population worldwide and in 8 geographical regions using statistical data on the incidence of malignant tumors in 2008, ie the number of new cases of oncopathology in the population, whose development could be prevented by specific directed effects.
In the case of a pronounced relationship, it was legitimate to say that the presence of an infectious disease is accompanied by the development of a greater number of cancer cases compared to the general population. Estimates of the number of infectious disease cases and the relative risk of developing malignant tumors have been made using previously published data. The authors used data from a number of sources, including GLOBOCAN (statistics on the incidence of 27 malignant tumors in 184 countries).
Of the 12.7 million new cases of malignant tumors diagnosed in 2008, the proportion of infectious cases was 16.1%, or approximately 2 million; for comparison, in 2004, the WHO calculated the relative share of a combination of 9 risk factors linked to lifestyle and the environment (smoking, alcohol abuse, overweight, etc.) in the development of oncopathology, which amounted to 35%. This indicator in less developed countries surpassed that of more developed countries (22.9% vs 7.4%) with fluctuations from 3.3% in Australia and New Zealand to 32.7 % in sub-sugar Africa. Helicobacter pylori, hepatitis B and C viruses and papillomaviruses have contributed to the development of more than 1.9 million malignant neoplasms, with localization in the stomach, liver and cervix. the uterus. Among women, cervical cancer accounted for about half of the infection-related cancer outbreaks, in men, stomach and liver cancer accounted for more than 80%. About 30% of infectious cancer cases have been reported in people under the age of 50. HIV was not a primary infectious agent because it indirectly causes tumors, in particular due to the development of immunosuppression, and it was therefore considered to be a cofactor.
Thus, each year, approximately 2 million cases of malignant neoplasms are caused by infectious agents. Active use of existing methods for the prevention of infectious diseases, such as vaccination, safe injection, and the use of antimicrobial agents, can significantly halt the widespread growth of oncopathology in the future.
A companion article noted that given the widespread prevalence and availability of effective and relatively inexpensive HPV and hepatitis B vaccines, the increase in the percentage of the population reached by vaccination should be a priority in countries where the cancer incidence rate is high. However, the articles do not indicate the source of funding for such important preventive work.