Abstract Breast cancer (BC) is the leading cause of death by this disease in women worldwide. Among the factors involved in tumorigenesis, long non-coding RNAs (lncRNAs) and their differential expression have been associated. Differences in gene expression may be triggered by variations in DNA sequence, including single nucleotide polymorphisms (SNPs). In the present study, we analyzed the rs527616 (C>G), located in the lncRNA AQP4-AS1, using PCR-SSP in 306 BC patients and 312 controls, from a Brazilian population. In the BC group, the frequency found for CG heterozygotes was above the expected and the overdominant model is the best one to explain our results (OR: 1.70, IC 95%: 1.23-2.34, P<0.001). Furthermore, the SNP were associated with age at BC diagnosis and the risk genotype more frequent in the older age group. According to TCGA data, AQP4-AS1 is down-regulated in BC tissue, and the overexpression is associated with better prognoses, including Luminal A, HER2-, stage 1 of disease and smaller tumor. In conclusion, the CG genotype is associated with increased susceptibility in the southern Brazilian population. This SNP is mapped in the lncRNA AQP4-AS1, showing differential expression in BC samples. Based on these results, we emphasize the potential of the role of AQP4-AS1 in cancer.

Resumo Introdução: o câncer de mama é a segunda causa de morte no mundo, sendo 90% dessas mortes decorrentes de metástases. A metaloprotease de matriz 2 (MMP-2) possui atividade de gelatinase capaz de degradar o principal constituinte do microambiente tumoral, o colágeno do tipo IV. Há duas proteínas bem estabelecidas utilizadas como marcadores na prática clínica para o câncer de mama, os receptores de estrógeno (RE) e de progesterona (RP). Embora a presença desses receptores tenha sido associada a um melhor prognóstico, a perda delas pode ocorrer durante a progressão do tumor, com subsequente resistência à terapia hormonal. Objetivo: analisar a correlação entre as proteínas MMP-2, RE e RP por imuno-histoquímica e estabelecer o processo metastático em tumores de mama primários. Método: amostras de tumor de mama (n=44) foram analisadas por imuno-histoquímica para MMP-2, receptor de estrógeno e progesterona. Resultados: observou-se que 90% das pacientes que tinham metástases e morreram apresentaram coloração positiva para a MMP-2 (p=0,0082 para ambos). Usando a análise de Kaplan-Meier, verificou-se que as pacientes RE negativas, também positivas para MMP-2, apresentaram sobrevida livre de doença (SLD) e sobrevida global (SG) (p=0,012 e p=0,005, respectivamente) piores quando comparadas às pacientes MMP-2 negativas. Resultados semelhantes foram encontrados em pacientes RP negativas para SLD (p=0,077) e SG (p=0,038). Conclusão: embora o número de amostras avaliadas tenha sido baixo (n=44), esses dados iniciais permitem inferir que a MMP-2 em combinação com os marcadores já bem estabelecidos poderia ajudar na previsão do surgimento de metástase e morte em pacientes com câncer de mama.

Summary Introduction: Breast cancer is the most cause of death, and approximately 90% of these deaths are due to metastases. Matrix metalloproteinase-2 (MMP-2) gelatinase activity is able to degrade a major constituent of the tumor microenvironment, type IV collagen. Two well-established proteins used as markers in clinical practice for breast cancer are the receptors for estrogen (ER) and progesterone (PR). Although the presence of these receptors has been associated with a better prognosis, loss of these proteins can occur during tumor progression, with subsequent resistance to hormone therapy. Objective: To study the correlation among MMP-2, ER, and PR, as well as the establishment of the metastatic process in primary breast tumors. Method: Breast cancer samples (n=44) were analyzed by immunohistochemistry for MMP-2, ER, and PR. Results: We observed that 90% of patients who had metastases and died showed positive staining for MMP-2 (p=0.0082 for both). Using Kaplan-Meier analysis, we found that negative ER patients who were also positive for MMP-2 had even worse disease-free survival (DFS) and overall survival (OS) (p= 0.012 and p=0.005, respectively). Similar results were found in PR-negative patients for DFS (a trend p=0.077) and OS (p=0.038). Conclusion: Regardless of our small sample size (n=44), the data obtained strongly suggest that MMP-2 in combination with already well-established markers could help to predict the emergence of metastases and death in patients with breast cancer.

A variabilidade das regiões heterocromática e eucromática do cromossomo Y humano foi estudada, pelo emprego de uma metodologia da análise quantitativa e através de medidas densitométricas, em 60 negros normais e não aparentados (30 com sobrenomes de conotação religiosa e 30 sem sobrenome de conotação religiosa) de Salvador, Bahia. Trinta indivíduos caucasóides de origem européia, normais e não aparentados, de Curitiba, Paraná, constituíram o grupo controle. A região heterocromática e o tamanho total do cromossomo Y foram, em média, maiores nos caucasóides do que nos negros com e sem sobrenomes de conotação religiosa, sendo as médias observadas nestes últimos intermediárias entre as dos caucasóides e dos negros com sobrenome de conotação religiosa. Estes dados estão de acordo com os de publicações anteriores, que demonstram que nos negros com sobrenomes de conotação religiosa há mais ancestrais negros do que naqueles sem sobrenomes de conotação religiosa.

The variability of the lengths of the heterochromatic and euchromatic segments of the human Y chromosome was studied by a quantitative method of densitometric measurement in 60 normal and unrelated black individuals (30 with and 30 without devotional surnames), living in Salvador, Bahia, northeastern Brazil. Thirty normal and unrelated Caucasian individuals of European origin, living in Curitiba, Paraná, south Brazil, were included as controls. The heterochromatic segment and total Y chromosome lengths were greater in caucasians than in blacks without devotional surnames, and these were greater than in blacks with devotional surnames. These findings are in agreement with previous reports of a higher percentage of black ancestry in blacks carrying devotional surnames than those carrying non-devotional ones.