The microbiome is able to modulate immune responses, alter the physiology of the human organism, and increase the risk of viral infections and development of diseases such as cancer. In this review, we address changes in the cervical microbiota as potential biomarkers to identify the risk of cervical intraepithelial neoplasia (CIN) development and invasive cervical cancer in the context of human papillomavirus (HPV) infection. Current approaches for clinical diagnostics and the manipulation of microbiota with the use of probiotics and through microbiota transplantation are also discussed.

Objective: To identify a new circulating recombinant form (CRF) of HIV-1 comprising two circulating subtypes in the southern region in Brazil, subtypes B and C. Methods: A total of 152 HIV-positive patients followed at two hospitals in southern Brazil had their viral pol genes isolated by reverse transcriptase–polymerase chain reaction (PCR) from plasma. PCR products were sequenced and phylogenetically analysed using HIV-1 subtype reference sequences. Six full-length subtype C viruses from Brazil previously described as ‘pure’ strains were included in the analysis. Sequences suggestive of recombination were analysed by bootscanning and phylogenetic analyses of separate fragments. The common ancestry of recombinant strains was evaluated by similarity plot and informative site analyses. Results: HIV-1 subtypes commonly found in Brazil (B, C and F1) were observed. Sixty-two viruses were initially assigned as subtype C, but 15 viruses clustered in a separate internal clade. Pol from two full-length genomes of subtype C viruses grouped together with those samples. Bootscanning analysis showed that all 17 viruses had the same recombinant structure, with a 240 base pair fragment of subtype B in the middle of the reverse transcriptase pol region. Subtype B assignment of this fragment was confirmed by phylogenetic analyses using different methods of tree inference and cluster robustness tests. Mosaics were shown to have a common ancestry. Conclusion: As CRF_BC represents 11% of the HIV-1 viruses circulating in the southern region of the country, which borders several south American countries, the assessment of its spread is of pivotal importance to the HIV/AIDS epidemic in Brazil and Latin America.

The APOBEC family of proteins comprises deaminase enzymes that edit DNA and/or RNA sequences. The APOBEC3 subgroup plays an important role on the innate immune system, acting on host defense against exogenous viruses and endogenous retroelements. The role of APOBEC3 proteins in the inhibition of viral infection was firstly described for HIV-1. However, in the past few years many studies have also shown evidence of APOBEC3 action on other viruses associated with human diseases, including HTLV, HCV, HBV, HPV, HSV-1, and EBV. APOBEC3 inhibits these viruses through a series of editing-dependent and independent mechanisms. Many viruses have evolved mechanisms to counteract APOBEC effects, and strategies that enhance APOBEC3 activity constitute a new approach for antiviral drug development. On the other hand, novel evidence that editing by APOBEC3 constitutes a source for viral genetic diversification and evolution has emerged. Furthermore, a possible role in cancer development has been shown for these host enzymes. Therefore, understanding the role of deaminases on the immune response against infectious agents, as well as their role in human disease, has become pivotal. This review summarizes the state-of-the-art knowledge of the impact of APOBEC enzymes on human viruses of distinct families and harboring disparate replication strategies.

In diseases where epigenetic mechanisms are changed, such as cancer, many genes show altered gene expression and inhibited genes become activated. Human endogenous retrovirus type K (HERV-K) expression is usually inhibited in normal cells from healthy adults. In tumor cells, however, HERV-K mRNA expression has been frequently documented to increase. Importantly, HERV-K-derived proteins can act as tumor-specific antigens, a class of neoantigens, and induce immune responses in different types of cancer. In this review, we describe the function of the HERV-K HML-2 subtype in carcinogenesis as biomarkers, and their potential as targets for cancer immunotherapy.

Most of the current knowledge on antiretroviral (ARV) drug development and resistance is based on the study of subtype B of HIV-1, which only accounts for 10% of the worldwide HIV infections. Cumulative evidence has emerged that different HIV types, groups and subtypes harbor distinct biological properties, including the response and susceptibility to ARV. Recent laboratory and clinical data highlighting such disparities are summarized in this review. Variations in drug susceptibility, in the emergence and selection of specific drug resistance mutations, in viral replicative capacity and in the dynamics of resistance acquisition under ARV selective pressure are discussed. Clinical responses to ARV therapy and associated confounding factors are also analyzed in the context of infections by distinct HIV genetic variants.

As a middle-income country, Brazil has one of the largest public health systems worldwide, which deals with free and universal access to health care. Regarding cervical cancer, the country possesses a large infrastructure for the screening of premalignant and malignant lesions, but yet based on old technology, having Papanicolaou as the major screening method, followed by colposcopy and treatment. Also, large disparities in access are present, which makes effectiveness of screening and treatment in different regions of the country highly unequal. In this review, we describe and evaluate the current screening, treatment and prophylactic (HPV vaccination) strategies to combat cervical cancer in Brazil, and discuss potential incorporation of more recent technologies in these areas in the country to pave its way toward cervical cancer elimination.