A comparative immunohistochemical analysis of cortactin in orthokeratinized odontogenic cyst (OOC), sporadic odontogenic keratocyst (OKC), and syndromic OKC.

OBJECTIVES: To evaluate and compare the immunohistochemical expression of cortactin in the epithelial lining of orthokeratinized odontogenic cyst (OOC), sporadic odontogenic keratocyst (OKC), and syndromic OKC. METHODS: Formalin-fixed paraffin-embedded tissue blocks of histopathologically diagnosed cases of OOC, OKC, syndromic OKC, normal buccal mucosa (NBM), and oral squamous cell carcinoma (OSCC) were examined for immunohistochemical expression of cortactin. Clear brown cytoplasmic and membranous staining was considered positive. RESULTS: A statistically significant difference was observed between OOC and syndromic OKC (p < 0.001), as well as between sporadic OKC and syndromic OKC (p < 0.001). Although not statistically significant, the expression of cortactin was slightly higher in the basal layer of NBM (mean = 0.47), OOC (mean = 0.27), sporadic OKC (mean = 0.47) syndromic OKC (mean = 1.53), and OSCC (mean = 0.67) than in the parabasal layers of NBM (mean = 0.27), OOC (mean = 0.20), sporadic OKC (mean = 0.47), syndromic OKC (mean = 1.27), and OSCC (mean = 0.60). CONCLUSION: The expression of cortactin in the basal layer may suggest the formation of invadopodia in the basal layer where the invasion mechanism occurs. This finding is further supported by the higher localization of cortactin in areas of epithelial budding and daughter cysts in syndromic OKC, thereby reaffirming its possible association with recurrence.