Imunoexpressão de Efrina-A1, Eph-A1 e Eph-A2 em adenoma pleomórfico e carcinoma mucoepidermoide glandulares salivares

Abstract

Ephrins and their receptors have become the target of research related to tumor etiopathogenesis, as they participate in bidirectional intracellular signaling that modulate various cellular and tumor phenomena, but little is known about their action in salivary glandular neoplasms. The immunoexpression of Ephrin-A1, Eph-A1 and Eph-A2 was evaluated in a sample of 8 pleomorphic adenomas (PA) and 8 salivary glandular mucoepidermoid carcinomas (CME) in relation to their histomorphological parameters (criteria from Soares et al., 2009 and Brandwein et al., 20091). Cytoplasmic and nuclear immunoexpression percentages were established in five fields of greatest immunoreactivity (400x) to anti-Ephrin-A1 monoclonal and anti-Eph-A1 and anti-Eph-A2 polyclonal antibodies. Data were analyzed using the Mann-Whitney and Spearman correlation tests (p < 0.05). High percentages of cytoplasmic immunoexpression of Ephrin-A1 were observed, with a slight higher expression in CME and low nuclear percentages of this ephrin, mainly in AP, with a significant difference in its nuclear expression in relation to the degree of malignancy of the CME (p <0.05). Eph-A1 had high cytoplasmic expression in the sample, slightly higher in AP and nuclear expression in all CME and in 87.5% of AP, with no significant difference in cytoplasmic and nuclear expression in relation to the histomorphological parameters of the sample. Eph-A2 exhibited high cytoplasmic expression, with a higher tendency in CME and high nuclear expression in the sample, mainly in AP, without significant differences in the expression of Eph-A2 in cytoplasm and nucleus in relation to the histomorphological parameters of the sample. In AP, there was a negative correlation between cytoplasmic Ephrin-A1 and nuclear Eph-A1 expressions (r=-0.762; p=0.028). In CME, there was a negative correlation between cytoplasmic Eph-A1 and nuclear Ephrin-A1 expressions (r=-0.807; p=0.015). In conclusion, the greater cytoplasmic expression of Ephrin-A1 in AP and CME suggests its action in salivary gland tumorigenesis. The nuclear expression of Eph-A1 suggests its action in reverse signaling pathways, probably regulating events in the development of AP and CME. The higher expression of Eph-A2 in CME suggests this expression profile in malignant tumorigenesis. The high cytoplasmic expression of proteins in relation to the histomorphological parameters of the sample, especially in CME of higher degree of malignancy, suggests that they may play a role in regulating the pathogenesis of these lesions, however the low nuclear expression, mainly of Ephrin-A1, suggests that this protein expression profile is little involved in the tumorigenesis of AP and CME.