engleski

Immunohistochemical expression of CD31 and Ki67 markers in canine oral melanomas

Canine oral melanoma (COM) is a malignant tumour with high metastatic potential. Vascular mimicry (VM) is a process in which tumour cells form channels without the presence of endothelial cells. It allows additional tumour vascularization and is associated with a poor prognosis. This study investigated blood vessels, potential VM, and tumour cell proliferation by using CD31 and Ki67 IHC markers in COM samples. Histopathology and immunohistochemistry (IHC) were performed on 24 FFPE COM samples. The expression of CD31 and Ki67 were examined in relation with mitotic index (MI). The number of Ki67 positive cells was estimated per 1, 000 tumour cells. Regarding the CD31 marker, the number of immunolabelled and CD31 negative vascular spaces was analyzed in 4 HPF. The Spearman’s correlation coefficient test was used to analyze observed variables statistically. High MI was detected in most COM (75% ; n = 18) (cutoff value ≤4 ; >4/10HPF). CD31 positive blood vessels were found in all COM. However, CD31 negative vascular spaces, interpreted as potential VM, were found in 33.33% (n = 8) of samples. The correlation between MI, CD31 and Ki67 expression was not statistically significant. There was a positive correlation between MI and Ki67 as well as Ki67 and CD31 negative vascular spaces (p<0, 05). In conclusion, ignoring the small number of samples, higher expression of Ki67 in tumour cells with CD31 negative vascular spaces suggestive of VM may indicate more aggressive biological behaviour and provide a more accurate prognosis of COM.

immunohistochemistry, CD31, Ki67, oral melanoma, dog

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