Comparative expression of cyclooxygenase 2 and Ki67 in amelanotic and conventional oral melanomas

Abstract
Oral melanomas have some histopathological resemblance with its cutaneous counterpart; however, an aggressive behavior is more common in tumors that occur in the oral cavity. Several markers have been suggested as indicative of tumoral progression and aggressiveness, such as cyclooxygenase 2 (COX-2) and Ki67. In this study, we have compared the expression of COX-2 and Ki67 in a series of amelanotic (n=7) and melanotic oral melanomas (n=22). The cases were selected from 4 pathology laboratories and submitted to the immunohistochemical (IHC) reactions. We analyzed the IHC staining based on a qualitative ? using visual scores; and a computer-assisted method (quantitative) using scanned slides and software for digital analysis. COX-2 was expressed in all oral melanomas; however, its intensity was significantly higher in the amelanotic ones (P<0.001). Similarly, a high Ki67-positivity index was observed in the amelanotic than melanotic ones (P<0.001). Based on these results, we suggest that amelanotic oral melanomas have marked pro-inflammatory and high-proliferative phenotype, justifying their more aggressive behavior compared with the melanotic ones.
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Bibliographic reference
Soares, Ciro Dantas ; Hernández Guerrero, Juan Carlos ; Andrade, Bruno Augusto Benevenuto de ; Romañach, Mário José ; Mosqueda Taylor, Adalberto ; Carlos, Román ; Macedo, Madja Ruanna Soares ; Almeida, Oslei Paes de ; Jorge, Jacks. Comparative expression of cyclooxygenase 2 and Ki67 in amelanotic and conventional oral melanomas. En: Medicina oral, patología oral y cirugía bucal. Ed. inglesa, 25 6 2020: 15-