Differential proteomic comparison of breast cancer secretome using a quantitative paired analysis workflow

Abstract Background Worldwide, breast cancer is the main cause of cancer mortality in women. Most cases originate in mammary ductal cells that produce the nipple aspirate fluid (NAF). In cancer patients, this secretome contains proteins associated with the tumor microenvironment. NAF studies are challenging because of inter-individual variability. We introduced a paired-proteomic shotgun strategy that relies on NAF analysis from both breasts of patients with unilateral breast cancer and extended PatternLab for Proteomics software to take advantage of this setup. Methods The software is based on a peptide-centric approach and uses the binomial distribution to attribute a probability for each peptide as being linked to the disease; these probabilities are propagated to a final protein p-value according to the Stouffer’s Z-score method. Results A total of 1227 proteins were identified and quantified, of which 87 were differentially abundant, being mainly involved in glycolysis (Warburg effect) and immune system activation (activated stroma). Additionally, in the estrogen receptor-positive subgroup, proteins related to the regulation of insulin-like growth factor transport and platelet degranulation displayed higher abundance, confirming the presence of a proliferative microenvironment. Conclusions We debuted a differential bioinformatics workflow for the proteomic analysis of NAF, validating this secretome as a treasure-trove for studying a paired-organ cancer type

Mutações no gene TP53 em tumores malignos de mama: associação com fatores de risco e características clínico-patológicas, inclusive risco de óbito, em pacientes residentes no Rio de Janeiro TP53 mutation in malignant breast tumors: association with risk factors and clinical-pathological characteristics, including risk of death, in patients from Rio de Janeiro

No Brasil, o câncer de mama é a primeira causa de óbito por câncer entre mulheres, sendo o Rio de Janeiro o Estado que apresenta o maior coeficiente de mortalidade do país. Estudos que avaliam a sobrevida por câncer de mama têm indicado que vários fatores de ordem genética e molecular podem influenciar a evolução dos casos. O objetivo deste trabalho foi descrever mutações no gene TP53 em 120 pacientes com diagnóstico de carcinoma invasivo de mama, recrutadas no Instituto Nacional de Câncer (INCA), Rio de Janeiro, entre 1995 a 1997, e analisar as possíveis associações entre fatores de risco e presença de mutação e entre características do tumor, incluindo estas mutações e o risco de óbito. A análise molecular detectou 24 mutações no gene TP53 em 22 casos (18,3%), sendo que 2 casos apresentaram 2 mutações cada e, em um caso observamos o polimorfismo no éxon 6. As mutações encontradas eram: 14 com troca de sentido; 2 sem sentido; 2 silenciosas; 2 deleções; 1 inserção e 3 localizadas em íntron. Em relação aos fatores de risco estudados em associação à presença de mutação, observou-se que apenas o consumo de tabaco mostrou associação negativa (OR ajustado= 0,24 (0,06-0,88)). A análise multivariada utilizada para avaliar as características tumorais associadas ao risco de óbito mostrou que apenas a agressividade do tumor apresentou OR indicativo de risco (3,98, IC 95% 1,25-12,72). Estes resultados corroboram outros estudos que mostram que a mutação no gene TP53 pode ser um indicador de tumores de mama biologicamente mais agressivos, apesar de não ser o único parâmetro a ser considerado.<br>Breast cancer is the leading cause of death due to cancer among women in Brazil and, the State of Rio de Janeiro presents the highest mortality coefficient of this disease in the country. Studies have shown that many genetic and molecular factors may be related to the outcome of cases. The aim of this study was to describe the frequency and types of mutations in the tumor suppressor gene TP53 in 120 patients with diagnosis of invasive breast carcinoma recruited from the Instituto Nacional de Câncer (INCA), Rio de Janeiro from1995 to 1997, and to analyze the associations between these mutations and risk factors, and tumor characteristics, including the presence of TP53 mutations, and risk of death. The molecular analysis detected TP53 alterations in 22 cases (18.3%), of which 2 cases presented 2 mutations each; a polymorphism in exon 6 was observed in 1 case. The mutations found were: 14 missense, 2 nonsense, 2 silent, 2 deletions, 1 insertion and 3 located in introns which probably did not change the protein. The analysis of risk factors in relation to TP53 mutations showed that only tobacco consumption had an association (adjusted OR = 0.24 (0.06-0.88)). Multivariate analysis showed that only tumor aggressiveness showed an OR indicative of risk (3.98, IC 95% 1.25-12.72).These results are in agreement with previous studies, which report that the presence of TP53 mutations may indicate more aggressive breast tumors biologically although this is not the only parameter to be considered