DNA base excision repair and nucleotide excision repair proteins in malignant salivary gland tumors.

Fernanda Aragão Felix, Leorik Pereira da Silva, Maria Luiza Diniz de Sousa Lopes, Ana Paula Veras Sobral, Roseana de Almeida Freitas, Lélia Batista de Souza, Carlos Augusto Galvão Barboza

Archives of oral biology 2021 Jan

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To analyze the immunohistochemical expression of the base excision repair (BER) proteins apurinic/apyrimidinic endonuclease 1 (APE1) and X-ray repair cross-complementing protein 1 (XRCC1) and nucleotide excision repair (NER) protein xeroderma pigmentosum group F (XPF) in malignant salivary gland tumors (MSGTs). Sixty-two cases of MSGTs were selected, including 14 acinic cell carcinomas (AcCC), 15 polymorphous adenocarcinomas (PAC), 16 adenoid cystic carcinomas (ACC), and 17 mucoepidermoid carcinomas (MEC). The specimens were submitted to quantitative immunohistochemical analysis. All MSGTs exhibited nuclear or nucleo-cytoplasmic immunostaining of APE1, XRCC1 and XPF, with a high percentage of positive cells (median = 78.31, 70.48 and 75.46, respectively). XRCC1 expression was higher in PAC compared to MEC (p = 0.032). Nuclear APE1 immunostaining was significantly higher than nucleo-cytoplasmic expression in the selected MSGTs (p < 0.0001). APE1 expression was significantly associated with T1-T2 tumors in ACC (p = 0.006). Increased expression of XPF was associated with age older than 60 years in MEC (p = 0.015) and with ACC involving the minor salivary gland (p = 0.012), while a lower expression was found in AcCC and ACC patients treated by surgery combined with adjuvant therapy (p = 0.036 and p = 0.020, respectively). Low expression of XRCC1 in the nucleus (p = 0.028) and concomitant expression of this protein in the nucleus/cytoplasm were associated with a lower overall 5-year survival rate (p = 0.017). This study showed that BER and NER proteins evaluated are highly expressed in the MSGTs studied, indicating mechanisms of genotoxic control in these tumors. In addition, the dysregulation of XRCC1 expression was a prognostic predictor in MSGTs analyzed. Copyright © 2020 Elsevier Ltd. All rights reserved.

Citation

Fernanda Aragão Felix, Leorik Pereira da Silva, Maria Luiza Diniz de Sousa Lopes, Ana Paula Veras Sobral, Roseana de Almeida Freitas, Lélia Batista de Souza, Carlos Augusto Galvão Barboza. DNA base excision repair and nucleotide excision repair proteins in malignant salivary gland tumors. Archives of oral biology. 2021 Jan;121:104987