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Os tumores malignos de glândula salivar (TMGS) são lesões raras, heterogêneas e de prognóstico variável. As células dos mamíferos estão sujeitas a milhares de modificações espontâneas na molécula de ácido desoxirribonucleico (DNA). A proteína endonuclease apúrica ou apirimídica 1 (APE1) e a proteína 1 de complementação cruzada de reparo de raios-x (XRCC1) são dois componentes importante da via de reparo por excisão de base (BER), e a proteína fator de complementação F do xeroderma pigmentoso (XPF), da via de reparo por excisão nucleotídeo (NER). Este estudo analisou a expressão imuno-histoquímica das proteínas APE1 e XRCC1 da via BER, e XPF da via NER, em amostra de tumores primários de carcinoma de células acinares (CCA), adenocarcinoma polimorfo (AcP), carcinoma adenoide cístico (CAC) e carcinoma mucoepidermoide (CME). Um total de 62 TMGS foram incluídos e submetidos à imuno-histoquímica contra os anticorpos selecionados, correspondendo a 14 CCA, 15 AcP, 16 CAC e 17 CME. As células do parênquima tumoral foram avaliadas quantitativamente, a partir de fotomicrografias de 5 campos (em aumento de 400x), por um único avaliador. Foram consideradas células imunorreativas aquelas com coloração acastanhada no núcleo e/ou núcleo/citoplasma, independente da intensidade. As células imunomarcadas e negativas foram contadas nos 5 campos, estabelecendo o porcentual de células positivas em relação ao número total de células contadas. Ademais, estabeleceu-se a razão núcleo ou núcleo/citoplasma, inferindo se a localização era predominantemente uni ou bicompartimental. Os testes estatísticos incluíram o exato de Fisher, Mann-Whitney, KruskalWallis, correlação de Spearman e log-rank para comparação das curvas de sobrevida global construídas pelo método Kaplan-Meier. O nível de significância foi estabelecido em 5%. Todos os TMGS selecionados marcaram para APE1, XRCC1 e XPF. Não houve diferença entre a expressão de APE1 e XPF entre os tumores estudados. Para XRCC1, contudo, observou-se diferença significativa entre AcP e CME (p=0.032). A marcação nuclear de APE1 foi estatisticamente maior nos TMGS selecionados (p<0.0001). Houve relação estatística de APE1 com tumores T1-T2 no CAC (p=0.006), bem como de aumento de XPF em pacientes com CME acima de 60 anos (p=0.015) e CAC em glândula salivar menor (p=0.012), embora tenha reduzido em pacientes tratados com cirurgia associado à terapia adjuvante no CCA e no CAC (p=0.036 e p=0.020, respectivamente). A baixa expressão de XRCC1 no núcleo (p=0.028) ou a expressão de XRCC1 concomitante no núcleo e no citoplasma (p=0.017) foram associadas com menor taxa de sobrevida global em 5 anos. Finalmente, o teste de correlação de Spearman demonstrou correlação positiva entre a APE e XRCC1 em todos os TMGS analisados, embora a correlação entre as três proteínas (APE1, XRCC1 e XPF) tenha sido observada apenas em CAC e CME (p<0.05). Este trabalho demonstrou alta expressão das proteínas de reparo APE1, XRCC1 e XPF em CCA, AcP, CAC e CME, o que pode sugerir atividade reguladora relacionada ao controle genotóxico dessas proteínas nos TMGS (AU).

Malignant salivary gland tumors (MSGT) are rare, heterogeneous lesions with a variable prognosis. Mammalian cells are subject to thousands of spontaneous changes in the deoxyribonucleic acid (DNA) molecule. The apuric or apyrimidic endonuclease protein 1 (APE1) and the X-ray crossover complementation protein 1 (XRCC1) are two important components of the base excision repair pathway (BER), and the complementation factor protein F of the xeroderma pigmentosum (XPF), the nucleotide excision repair pathway (NER). This study analyzed the immunohistochemical expression of APE1 and XRCC1 proteins of the BER pathway, and XPF of the NER pathway, in a sample of primary tumors of acinar cell carcinoma (ACC), polymorphic adenocarcinoma (PAC), adenoid cystic carcinoma (AdCC) and mucoepidermoid carcinoma (MEC). A total of 62 MSGT were included and submitted to immunohistochemistry against the selected antibodies, corresponding to 14 ACC, 15 PAC, 16 AdCC, and 17 MEC. The tissue sections were subjected to immunohistochemistry for APE1, XRCC1 and XPF. The cells of the tumor parenchyma were quantitatively evaluated, using photomicrographs of 5 fields (in 400x magnification), by a single evaluator. Immunoreactive cells were those with brownish color in the nucleus and/or nucleus/ cytoplasm, regardless of intensity. Immunomarked and negative cells were counted in the 5 fields, establishing the percentage of positive cells in relation to the total number of cells counted. In addition, it was established whether the nucleus or nucleus/cytoplasm ratio, inferring whether the location was predominantly uni or bicompartmental. Statistical tests included Fisher's exact, Mann-Whitney, Kruskal-Wallis, Spearman's correlation, as well as the log-rank for comparison of the overall survival built through Kaplan-Meier method. Significance was set at p<0.05. All selected MSGT scored for APE1, XRCC1 and XPF. There was no difference between the expression of APE1 and XPF among the studied tumors. For XRCC1, however, there was a significant difference between PAC and MEC (p=0.032). Nuclear labeling of APE1 was statistically higher in the selected MSGT (p<0.0001). There was a statistical relationship between APE1 and T1-T2 tumors in the AdCC (p=0.006), as well as an increase in XPF in patients with MEC over 60 years (p=0.015) and AdCC in a minor salivary gland (p=0.012), although reduced in patients treated with surgery associated with adjuvant therapy in ACC and AdCC (p=0.036 and p=0.020, respectively). The low expression of XRCC1 in the nucleus (p=0.028) or the expression of concomitant XRCC1 in the nucleus and cytoplasm (p=0.017) were associated with a lower overall 5-year survival rate. Finally, the Spearman correlation test demonstrated a positive correlation between APE and XRCC1 in all MSGT analyzed, although the correlation among the three proteins (APE1, XRCC1 and XPF) was observed only in AdCC and MEC (p<0.05). This study demonstrated high expression of the repair proteins APE1, XRCC1 and XPF in ACC, PAC, AdCC, and MEC, which may suggest regulatory activity related to the genotoxic control of these proteins in MSGT (AU).

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BACKGROUND AND OBJECTIVES: Apurinic/apyrimidinic endonuclease 1/redox effector factor-1 (APE1/Ref-1) is a multifunctional protein involved in the DNA base excision repair pathway, inflammation, angiogenesis, and survival pathways. We investigated serum APE1/Ref-1 in patients with coronary artery disease (CAD). SUBJECTS AND METHODS: Serum APE1/Ref-1 was measured with a sandwich enzyme-linked immunosorbent assay from 360 patients who received coronary angiograms. They were divided into two groups; a control (n=57) and a CAD group (n=303), the latter included angina (n=128) and myocardial infarction (MI, n=175). RESULTS: The levels of APE1/Ref-1 were higher in the CAD than the control (0.63±0.07 vs. 0.12±0.07 ng/100 µL, respectively; p<0.01). They were also higher in MI than angina (0.81±0.10 vs. 0.38±0.11 ng/100 µL, respectively; p<0.01) and different according to the thrombolysis in myocardial infarction (TIMI) flow (0.88±0.09 for TIMI flow 0, 1, 2 vs. 0.45±0.13 ng/100 µL for TIMI flow 3, p<0.01) in acute coronary syndrome. In correlation analysis, the levels of APE1/Ref-1 were positively correlated with Troponin I (r=0.222; p<0.0001) and N-terminal pro-B type natriuretic peptide (NT-proBNP, r=0.217; p<0.0001) but not high sensitivity to C-reactive protein. Also, they revealed a negative correlation with ejection fraction (EF, r=-0.221; p=0.002). However, there were no significant differences among the three groups, were divided by their levels of APE1/Ref-1, for major adverse cardiovascular events (death, recurrent MI, stroke, revascularization) (8.2 vs. 14.0 vs. 12.5%, p=ns). CONCLUSION: The levels of serum APE1/Ref-1 are elevated in CAD, and are higher in MI than in angina. They are correlated with Troponin I, NT-proBNP, and EF.

RESUMEN

BACKGROUND AND OBJECTIVES: Apurinic/apyrimidinic endonuclease 1/redox effector factor-1 (APE1/Ref-1) is a multifunctional protein involved in the DNA base excision repair pathway, inflammation, angiogenesis, and survival pathways. We investigated serum APE1/Ref-1 in patients with coronary artery disease (CAD). SUBJECTS AND METHODS: Serum APE1/Ref-1 was measured with a sandwich enzyme-linked immunosorbent assay from 360 patients who received coronary angiograms. They were divided into two groups; a control (n=57) and a CAD group (n=303), the latter included angina (n=128) and myocardial infarction (MI, n=175). RESULTS: The levels of APE1/Ref-1 were higher in the CAD than the control (0.63+/-0.07 vs. 0.12+/-0.07 ng/100 microL, respectively; p<0.01). They were also higher in MI than angina (0.81+/-0.10 vs. 0.38+/-0.11 ng/100 microL, respectively; p<0.01) and different according to the thrombolysis in myocardial infarction (TIMI) flow (0.88+/-0.09 for TIMI flow 0, 1, 2 vs. 0.45+/-0.13 ng/100 microL for TIMI flow 3, p<0.01) in acute coronary syndrome. In correlation analysis, the levels of APE1/Ref-1 were positively correlated with Troponin I (r=0.222; p<0.0001) and N-terminal pro-B type natriuretic peptide (NT-proBNP, r=0.217; p<0.0001) but not high sensitivity to C-reactive protein. Also, they revealed a negative correlation with ejection fraction (EF, r=-0.221; p=0.002). However, there were no significant differences among the three groups, were divided by their levels of APE1/Ref-1, for major adverse cardiovascular events (death, recurrent MI, stroke, revascularization) (8.2 vs. 14.0 vs. 12.5%, p=ns). CONCLUSION: The levels of serum APE1/Ref-1 are elevated in CAD, and are higher in MI than in angina. They are correlated with Troponin I, NT-proBNP, and EF.

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