Publications

OBJECTIVE

To conduct the first national biological and behavioral surveillance survey for HIV among MSM in Brazil.

DESIGN

A cross-sectional surveillance study utilizing Respondent Driven Sampling (RDS) in 10 cities, following formative research. Planned sample: 350 MSM reporting sex with another man in the last 12 months, at least 18 years of age, and residing in the city of the study.

METHODS

Conventional RDS recruitment. Results were calculated for each city using RDSAT 5.6. For the national estimate, a new individual weight using a novel method was calculated. The 10 cities were aggregated, treated as strata and analyzed using STATA11.0. Self-reported HIV status and logistic regression was used to impute missing values for serostatus, an important issue for RDSAT.

RESULTS

A total of 3859 MSM were interviewed. Sample was diverse, most self-identified as mulatto or black, were social class C or below, and had relatively low levels of education. More than 80% reported more than one partner in the last 6 months. Only 49% had ever tested for HIV. HIV prevalence among MSM ranged from 5.2 to 23.7% in the 10 cities (3.7-16.5% without imputation) and was 14.2% for all cities combined with imputation. The overall prevalence was two and three times higher than that estimated for female sex workers and drug users, respectively, in Brazil. Half of those who tested HIV positive were not aware of their infection.

CONCLUSION

The AIDS epidemic in Brazil is disproportionately concentrated among MSM, as has been found in other countries. Renewed efforts to encourage testing, prevention and treatment are required.

Despite advances in our understanding of breast cancer, patients with metastatic disease have poor prognoses. GATA3 is a transcription factor that specifies and maintains mammary luminal epithelial cell fate, and its expression is lost in breast cancer, correlating with a worse prognosis in human patients. Here, we show that GATA3 promotes differentiation, suppresses metastasis and alters the tumour microenvironment in breast cancer by inducing microRNA-29b (miR-29b) expression. Accordingly, miR-29b is enriched in luminal breast cancers and loss of miR-29b, even in GATA3-expressing cells, increases metastasis and promotes a mesenchymal phenotype. Mechanistically, miR-29b inhibits metastasis by targeting a network of pro-metastatic regulators involved in angiogenesis, collagen remodelling and proteolysis, including VEGFA, ANGPTL4, PDGF, LOX and MMP9, and targeting ITGA6, ITGB1 and TGFB, thereby indirectly affecting differentiation and epithelial plasticity. The discovery that a GATA3-miR-29b axis regulates the tumour microenvironment and inhibits metastasis opens up possibilities for therapeutic intervention in breast cancer.