Análise da porcentagem da DNA ploidia e de células em fase S, determinada por citometria de fluxo e por outras variáveis prognosticas em carcinomas primários de mama

Analisaram-se a DNA ploidia e a porcentagem de células em fase S, determinadas por citometria de fluxo, em biópsias de 69 carcinomas mamários. Outras variáveis prognosticas foram estudadas: 1. clínicas (raça, idade, estado menstruai, estadiamento, tamanho do tumor e a avaliação dos linfonodos axilares); 2. histológicas (comprometimento metastático dos linfonodos axilares, embolização de células neoplásicas em vasos linfáticos e sanguíneos, grau de diferenciação histológica, número de mitoses e necrose tumoral); 3. Bioquímicas (receptores de estradiol e progesterona). Cotejaram-se estas variáveis com o estudo da DNA ploidia e porcentagem de fase S. Notou-se haver uma associação significativa entre a DNA diploidia em pacientes com idade acima de 50 anos, tumores de tamanho ou igual a 2,0 cm, receptores de estradiol e receptores de progesterona. Observou-se também uma associação significativa entre a porcentagem de fase S >7,15 e pacientes na pré-menopausa, receptores de estradiol negativo e comprometimento metastático linfonodal. Constatou-se que as pacientes com tumores classificados como DNA aneuplóides, com fase S maior que 7,15, apresentaram metástases mais freqüentes e sobrevida menor que aquelas com tumores DNA diplóides e fase S menor que 7,15. Sob o ponto de vista do prognóstico pode-se constatar a importância do estudo do DNA, particularmente para o grupo pNO. Verificou-se a viabilidade de esta técnica ser realizada em nossa rotina para o estudo prognóstico do câncer de mama.

Polymorphisms in the melatonin receptor gene promoter and their associations with fertility characteristics in buffalo herd in Eastern Amazon

Buffalo production is spreading globally because of its economic advantage. Then, it has become necessary to improve the reproductive and productive efficiency of these animals, as well as to look for genetic factors that increase this efficiency. The objectives of this study were to characterize the promoter region of the melatonin 1A receptor gene (MTRN1A), to detect possible SNPs and associate them with fertility characteristics, and identify binding sites of transcription factors involved in the regulation of genetic expression in buffaloes in the Amazon. The conventional PCR method was carried out using the two primers designed from the reference sequence deposited in the GenBank AY52466.1. The products of the PCRs were purified, sequenced, and subsequently edited and aligned. Twenty-six SNPs were found, where 73% presented allele frequencies of wild nucleotides above 0.5, and 73% presented deviations from the Hardy-Weinberg equilibrium (P < 0.05) and F_IS varying between 0.06 and 1.00, characterizing high degrees of inbreeding within the population. A block of ACAA deletion (position -1483) was observed in 25% of samples. The associations between these SNPs and reproductive characteristics were observed for calving interval and 5 SNPs: -1289, -1139, -911, -724, and -656 (P < 0.05), and three other SNPs: -1395, -724, and -94 (P < 0.05) were associated significantly with age at first calving, and were not associated with calving concentration. The promoter region was characterized by the different types of binding factors, where only 11 sites are significantly strong enough for transcription factor bindings. The ACAA deletion also exhibited a strong association with transcription factors. As a result, it would be necessary to test the SNPs above with other reproductive characteristics of economic relevance to approve the gene as a strong candidate for the selection of buffaloes in the Amazon.

Polymorphisms in the leptin gene promoter in Brazilian beef herds

Brazil is the world's largest producer of beef cattle; however, the quality of its herds needs to be improved. The use of molecular markers as auxiliary tools in selecting animals for reproduction with high pattern for beef production would significantly improve the quality of the final beef product in Brazil. The leptin gene has been demonstrated to be an excellent candidate gene for bovine breeding. The objective of this study was to sequence and compare the leptin gene promoter of Brazil's important cattle breeds in order to identify polymorphisms in it. Blood samples of the Nellore, Guzerat, Tabapuã, and Senepol breeds were collected for genomic DNA extraction. The genomic DNA was used as a template for polymerase chain reaction (PCR) to amplify a 1575-bp fragment, which in turn was sequenced, aligned, and compared between animals of different breeds. Twenty-three single nucleotide polymorphic sites, including transitions and transversions, were detected at positions -1457, -1452, -1446, -1397, -1392, -1361, -1238, -963,-901, -578, -516, -483, -478, -470, -432, -430, -292, -282, -272, -211, -202, -170, and -147. Additionally, two insertion sites at positions -680 and -416 and two deletion sites at positions -1255 and -1059 were detected. As the promoter region of the leptin gene has been demonstrated to vary among breeds, these variations must be tested for their use as potential molecular markers for artificial selection of animals for enhanced beef production in different systems of bovine production in Brazil.

Corrigendum Polymorphism in the melatonin receptor gene in buffalo populations of the Brazilian Amazon - Genet. Mol. Res. 15 (2): gmr.15027960

The correction is only in the name of the first author and should be: E.M. Barbosa(1), B.B. Souza(2), R.C. Guimarães(2), J.S.N. Azevedo(3), E.C. Gonçalves(4), H.F.L. Ribeiro(2), S.T. Rolim Filho(2), E. Silva Filho(2).

Homology modeling and molecular dynamics of β-defensin II variants in Amazonian sheep

β-defensins are capable of creating pores in the bacterial membrane. In this study, we aim to determine the structure of 3 different sheep β-defensin 2 (SBD-2) sequences by molecular modeling. A herd of 47 sheep from the Centre for Ovine and Caprine Research of Pará was selected for this investigation. The AA, AG, and GG alleles were found on β-defensin sequences. We used homology modeling and molecular dynamic simulations to generate 3D models of peptides and they were successfully validated. The proteins are structurally very similar to classic defensins composed of 3 β-sheets and 3 disulfide bonds. Variations in the organization of the tertiary structure and distribution of charged residues were found between AA, AG, and GG alleles. In this study, we were able to characterize and show the structure of 3 SBD-2 gene variants for the first time in Amazonian sheep. Results demonstrated that these variants are similar in structures to classic β-defensins, but contain more positives charges, which may indicate an increase in efficacy.

Abstract P1-01-28: What is the actual impact of micrometastases in sentinel lymph nodes in regards to global survival and disease free survival

OBJECTIVE: Assess the clinical relevance of micro metastasis in sentinel lymph nodes in the overall survival and disease free survival of 1,211 patients undergoing sentinel lymph node biopsy.

METHODS: Retrospective cohort study including 1,211 patients undergoing consecutive SLB from 1998 to 2010. SLB were performed in patients with invasive carcinoma of the breast with clinically negative axilla. Age, tumor size, and histologic grades, estrogen and progesterone receptors expression, HER-2, lymphovascular invasion and size of metastases in lymph nodes were assessed. Tumor sizes were divided according to pathologic staging into pT1(&lt; 2,0mm) and pT2(&gt;2,0mm). Lymph nodes were classified as negative (pN0), positive with micro metastases with diameter ranging from 0,21mm to 2,0mm(pN1mi) and positive with macro metastases with diameter greater than 2,0mm(pN1). Statistical analyses were performed by the Likelihood ratio test or Chi-square test for insufficient samples between macro metastases and micro metastases in SLB. Time was considered in months and the overall follow-up time was 125 months and mean time was 65 months. Local regional and distant recurrences were considered as events for disease free survival and Kaplan-Meier survival functions were constructed, testing time between metastases sizes in SLB using the Log-rank test, with a significance level of 5%.

RESULTS: Of the studied variables, lymphovascular invasion(p = 0,068) and local regional and distant metastases(p = 0,002) had a statistically significant association with overall survival. Tumor size(p = 0,016); lymph vascular invasion(p = 0,002) and metastases types in sentinel lymph node(p &lt; 0,001) were associated to disease free survival. In the association tests with types of metastases in sentinel lymph node, the following were statistically significant: age(p = 0,004), tumor size(p &lt; 0,001), lymph vascular invasion(p &lt; 0,001) and local regional and distant recurrences. In the interim and final Cox regression analysis, macro metastases were the only statistically relevant factor for disease free survival(p &lt; 0,001).

CONCLUSION: The presence of micro metastases(pN1mi) in sentinel lymph node is associated to a prognosis similar to that of negative axilla patients(pN0), indicating that other risk factors for local regional and systemic recurrences should be taken into account.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-01-28.

P3-05-09: Comparison of Clinical Features and Patterns of Recurrence in Triple Negative Breast Cancers in Relation to Other Breast Cancers

Background : Breast cancer is an heterogeneous disease that have several and different biological characteristics and clinical behaviours. Of these, triple negative breast cancer represents 10–17%.This kind of tumor is characterized by estrogen, progesterone and HER2 receptor negativity and they are very aggressive, associated with poor prognosis, younger patients, high incidence of metastases and shorter relapse free survival. Triple negative breast tumours are more likely to experience local recurrence and distant relapse than other breast tumors, and require a more aggressive intervention.

PURPOSE : To compare the incidence of metastases, clinical features and outcome among patients with triple negative breast cancer and women with other types of breast cancer.

METHODS : This is a retrospective cohort analysis from 3893 patients with invasive breast cancer, diagnosed between January 2000 and April 2011 and attended at Brazilian Institute of Cancer Control (IBCC) in Sao Paulo, Brazil. Five hundred of these tumors were triple negative. We made a correlation of clinical variables such as age, tumor stage (TNM) and analysis of last follow-ups, such as metastases, disease free survival, death for tumor, death for other reasons, lost of follow-up, hygiene and diet regime (RHD) and local recurrence.

Results: The median follow-up for the cohort was 4,29 years. The mean age at diagnosis in triple negative group was 54,8 and for the others group was 57,1 years. Subgroup analysis of tumor grade showed that the triple negative breast tumors were diagnosed later (Stage II and III; p:&lt;0,0001). There was no difference in the appearance of the two types of tumors, when considering diagnose age. The incidence of metastases, death for tumor and free survival in triple negative tumors, respectively; 25,6%, 13,8% and 57,2% (p:&lt;0,0001) demonstrates the aggressiveness of this kind of tumor.

[Clinicopathological predictor factors of axillary involvement in patients with metastatic breast cancer in the sentinel lymph node]

PURPOSE

To evaluate which clinical, pathological or immunohistochemical factors may be predictive of metastatic involvement of other lymph nodes in patients with breast carcinoma undergoing sentinel lymph node biopsy (SLNB).

METHODS

A retrospective study carried out with 1,000 successive patients with SLNB from 1998 to 2008. Age, tumor size, histological grade, lymphovascular invasion, hormone receptor status and HER-2, size of metastasis and number of positive SLN were evaluated. The associations between the characteristics of the tumors and the types of metastases were evaluated through chi(2) corrected likelihood ratio tests for insufficient samples.

RESULTS

Mean age was 57.6 years and mean tumor size was 1.85 cm. A total of 72.2% SLN were negative and 27.8% were positive, but in 61.9% of the cases, the SLN was the only positive one, with 78.4% having macrometastases, 17.3% micrometastases and 4.3% isolated tumor cells (CTI). Tumor size was predictive of metastases in non-sentinel lymph nodes. After 54 months of follow-up, there were no recurrences in patients with CTI, but one local recurrence and two systemic recurrences were observed in the micrometastasis group, as well as four local and 30 distant metastases in the macrometastasis group.

CONCLUSIONS

Among the clinical parameters studied, only tumor size was correlated with metastatic involvement in axillary lymph nodes. The size of the metastases and the number of positive SLN also directly increased the possibility of systemic recurrence. The different rates of recurrence indicate that the biological significance of these types of metastases is different and that patients with SLN metastases may also have different risks of metastatic involvement of other axillary lymph nodes.

Gene expression profiling of clinical stages II and III breast cancer

Clinical stage (CS) is an established indicator of breast cancer outcome. In the present study, a cDNA microarray platform containing 692 genes was used to identify molecular differences between CSII and CSIII disease. Tumor samples were collected from patients with CSII or CSIII breast cancer, and normal breast tissue was collected from women without invasive cancer. Seventy-eight genes were deregulated in CSIII tumors and 22 in CSII tumors when compared to normal tissue, and 20 of them were differentially expressed in both CSII and CSIII tumors. In addition, 58 genes were specifically altered in CSIII and expression of 6 of them was tested by real time RT-PCR in another cohort of patients with CSII or CSIII breast cancer and in women without cancer. Among these genes, MAX, KRT15 and S100A14, but not APOBEC3G or KRT19, were differentially expressed on both CSIII and CSII tumors as compared to normal tissue. Increased HMOX1 levels were detected only in CSIII tumors and may represent a molecular marker of this stage. A clear difference in gene expression pattern occurs at the normal-to-cancer transition; however, most of the differentially expressed genes are deregulated in tumors of both CS (II and III) compared to normal breast tissue.

Detailed deletion mapping of chromosome segment 17q12-21 in sporadic breast tumours

Linkage studies have indicated that a gene on chromosome arm 17q, designated BRCA1, confers susceptibility to familial breast and ovarian cancer. To investigate the possible involvement of the BRCA1 gene in sporadic breast cancer we have analysed loss of heterozygosity (LOH) in a panel of 100 sporadic primary breast tumours using 10 PCR-based polymorphic markers from 17q12-21. Allele losses were detected in 40 of 100 tumours informative for at least one of the markers analysed. Of these 40 deleted tumours, 27 showed partial or interstitial loss on 17q. The pattern of LOH in the tumours with partial or interstitial LOH revealed three putative distinct deleted regions on 17q12-21. The first lies on the proximal long arm between D17S250 and THRA1; the second one lies between D17S776 and D17S579, the region containing the BRCA1 gene; and the third is telomeric to D17S733. The most frequently deleted region overlaps with the minimal region containing the BRCA1 gene, suggesting that this gene might also be associated with the development or progression of a proportion of sporadic breast tumours.