The expression of p63 and E-cadherin was studied in 22 oral squamous cell carcinomas in the dog according to immunohistochemical techniques. The association between these markers and clinicopathologic parameters was assessed. All tumor cells studied showed enhanced p63 expression. Regarding E-cadherin expression, 17 of 22 cases (77.3%) showed decreased immunoreactivity, and in 13 of 22 cases (59.1%), its expression was cytoplasmic. Neither p63 nor E-cadherin expression patterns were associated with tumor size, bone invasion, or lymph node metastasis. p63 score was related to proliferating cell nuclear antigen proliferative index (P ¼ .020). A statistically significant correlation between the expression patterns of these 2 markers was noted (P ¼ .026). Furthermore, they were related with tumor grade. An atypical p63 labeling and a cytoplasmic E-cadherin staining were statistically related with a higher tumor grade (P ¼ .022 and P ¼ .017, respectively). These findings suggest that changes in p63 and E-cadherin expression are frequent events in oral squamous cell carcinoma in dogs.
Keywords p63, E-cadherin, oral squamous cell carcinoma, dogSquamous cell carcinoma (SCC) is the second-most frequent oral cancer in dogs 23 and one of the most common head and neck neoplasias in humans. 2,42 In spite of its low metastatic rate, this tumor is locally aggressive to the bone and other surrounding soft tissues. 23 Regardless of location, stage, and treatment approaches, local recurrence is very common, especially when clean surgical margins cannot be achieved.The role of p63 and E-cadherin expression in human head and neck SCC has been extensively studied, mainly with reference to their implications for prognosis. 4,12 However, there is a lack of understanding of the molecular pathogenesis underlying this cancer. 37 Substantial data indicate that both proteins play a relevant role in SCC initiation and progression. 16,29 Abnormal expression patterns of these 2 proteins have been associated with the decrease of epithelial characteristics of squamous cells and the acquisition of a mesenchymal-like phenotype.