Pimenta José, Prada Justina, Pires Isabel, Cotovio Mário
CECAV-Veterinary and Animal Research Center, University of Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal.
Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 5000-801 Vila Real, Portugal.
Vet Sci. 2024 Feb 7;11(2):77. doi: 10.3390/vetsci11020077.
Equine melanocytic tumors are common and have an unusual benign behavior with low invasiveness and metastatic rates. However, tumoral mass growth is usually a concern that can have life-threatening consequences. COX-2 is related to oncogenesis, promoting neoplastic cell proliferation, invasion, and metastasis. The aim of this study was to evaluate the immunohistochemical expression of COX-2 in equine melanocytic tumors. Through extension and intensity of labeling, 39 melanocytomas and 38 melanomas were evaluated. Of the malignant tumors, 13.2% were negative and 63.2% presented a low COX-2 expression. Only 6 malignant tumors presented >50% of labeled cells, 18 malignant and 8 benign had an expression between 21 and 50%, 8 malignant and 3 benign tumors had an expression between 6 and 20%, 1 malignant tumor had an expression between 1 and 5%, and 5 malignant and 28 benign tumors had no expression. Malignant tumors showed higher COX-2 expression than did benign tumors, with statistically significant differences. The low levels of COX-2 may be one of the molecular reasons for the presence of expansive mass growth instead of the invasive pattern of other species, which is related to high COX-2 levels.
马黑素细胞瘤很常见，具有不寻常的良性行为，侵袭性和转移率较低。然而，肿瘤块的生长通常是一个令人担忧的问题，可能会产生危及生命的后果。COX-2与肿瘤发生有关，可促进肿瘤细胞的增殖、侵袭和转移。本研究的目的是评估COX-2在马黑素细胞瘤中的免疫组化表达。通过标记的范围和强度，对39例黑素细胞瘤和38例黑色素瘤进行了评估。在恶性肿瘤中，13.2%为阴性，63.2%表现为低COX-2表达。只有6例恶性肿瘤的标记细胞>50%，18例恶性和8例良性肿瘤的表达在21%至50%之间，8例恶性和3例良性肿瘤的表达在6%至20%之间，1例恶性肿瘤的表达在1%至5%之间，5例恶性和28例良性肿瘤无表达。恶性肿瘤的COX-2表达高于良性肿瘤，差异有统计学意义。COX-2水平低可能是马黑素细胞瘤出现膨胀性肿块生长而非其他物种侵袭性模式的分子原因之一，其他物种的侵袭性模式与高COX-2水平有关。
