HPV infections in Brazil and the potential risk of cancer
Learn more about the HPV virus and the need for new therapeutic strategies.
Human papillomavirus (HPV) is a group of viruses that are sexually transmitted through direct contact with infected skin or mucosa, or wounds in the genital, oral, and anal areas. HPV infections affect women and men and it is considered a silent disease, as only 5% of those infected usually have direct and "visual" effects of the virus, such as warts in the genital region, mouth and throat (1). These infections are classified into two types: transient and persistent. When the infection is completely eliminated from the body, regressing spontaneously and without medical intervention, it is considered transient or transitory. However, when it is caused by an oncogenic viral subtype (with the potential to cause cancer) and the primary infection persists, damage to the epithelium can occur, leading to the development of precursor lesions. In cases where these lesions are not quickly identified and treated, they may progress to cancer (2).
There are more than 200 HPV genotypes, among them, 12 are considered oncogenic. When there is infection by oncogenic forms of the virus, it is more serious. Types 16 and 18, considered high risk types, stand out as the main etiological agents for cervical cancer, present in 99% of clinical cases, with growing evidence linking the virus to anus, penis and vagina cancer (2).
HPV infection is very common and is considered the second most frequent cause of cancer in humans. In Brazil, in 2017, the prevalence of HPV infections was 54.6% among young people aged 16 to 25 years. And 38.4% of all cases had one of the most aggressive types of the virus (2).
As a strategy for control of cervical cancer in Brazil, there is a plan to prevent and reduce the incidence of this and other types of cancer induced by HPV. It is based on the supply of Gardasil vaccine offered by the National Immunization Program, recommended for girls aged between 9 and 13 years and boys aged between 11 and 14 years. However, prophylactic vaccines have greater benefit for individuals who have not yet been infected by the virus, and due to low vaccination coverage in Brazil, the incidence of cancer associated with HPV still represents a health problem. Another strategy is the recommendation of periodic cytopathological examination in asymptomatic women aged between 25 and 64 years. Through these tests, it is possible to detect and monitor pre-malignant lesions or tumors in early stages, contributing to the early diagnosis of the disease. The examination can be done at public health clinics or units, and performing it periodically allows a reduction in the incidence and mortality from the disease (2).
For the treatment of tumors induced by HPV, chemotherapy, radiotherapy, surgery or even a combination of these methods are currently performed (3). However, these strategies are very invasive and cause several side effects, significantly affecting the quality of life of patients. In addition, these treatments do not act specifically on tumor cells, meaning that they can cause death or removal of healthy tissues (4). Thus, the need for treatments that are less aggressive and that target tumor cells more specifically, making them less harmful to the patient's health, has increased in recent years.
In this context, thinking about providing a better quality of life to patients with this type of cancer, ImunoTera has been studying over the last few years, therapeutic strategies that are capable of restoring and activating functions of the immune system to treat lesions associated with HPV. The therapeutic vaccine of ImunoTera, in preclinical phase, showed synergism with other treatments, such as chemotherapy, with high efficacy in combating cancer induced by HPV. Learn more about our platform by clicking here.
1. Zhai K, Ding J, Shi HZ. HPV and lung cancer risk: A meta-analysis. J Clin Virol [Internet]. 2015;63:84–90. Available at: http://dx.doi.org/10.1016/j.jcv.2014.09.014
2. Instituto Nacional do Câncer. Estimativa Incidência de Câncer no Brasil - Biênio 2018-2019. Vol. 1, Inca. 2018. 124 p.
3. Zhou C, Tuong ZK, Frazer IH. Papillomavirus Immune Evasion Strategies Target the Infected Cell and the Local Immune System. Front Oncol [Internet]. 2 de agosto de 2019;9(August). Available at: https://www.frontiersin.org/article/10.3389/fonc.2019.00682/full
4. Cts EFFE, Pati IN, Und ENTS, Ch ER, Rapy RE. Efeitos colaterais da terapia antitumoral em pacientes submetidos à químio e à radioterapia. 2005;(1999):55–61.