Evaluation of c-Myc in odontogenic cysts and tumours-An immunohistochemical study

To assess immunohistochemically the presence of c-Myc both qualitatively and quantitatively in odontogenic cysts and tumours and to correlate the results with biological behaviour of these lesions.

Formalin-fixed, paraffin-embedded blocks of odontogenic cysts and tumours were retrieved from institutional archives. The study sample size was 45 (n = 45), which included 10 cases of odontogenic keratocyst cyst (n = 10), five cases of radicular cyst (n = 5), five cases of dentigerous cyst (n = 5), and 10 cases of solid ameloblastoma of which five cases are follicular (n = 5) and five cases are plexiform (n = 5), 10 cases of Adenomatoid odontogenic tumour (n = 10) and five cases of unicystic ameloblastoma (n = 5). Sections were taken and stained immunohistochemically using c-Myc and evaluated both for quantitative and qualitative analysis.

In the current study, the mean number of c-Myc positive cells in the odontogenic tumours was highest in solid Ameloblastoma (78.6 ± 11.59), followed by Adenomatoid odontogenic tumor (AOT) (75.30 ± 39.853) and least in unicystic ameloblastoma (56.6 ± 20.53). Among odontogenic cysts, the mean number of c-Myc positive cells was higher in Odontogenic keratocyst (OKC) (73.2 ± 17.937) compared to dentigerous cyst (28.0 ± 27.9) and radicular cysts (31.0 ± 31.7). The staining intensity varied in odontogenic cysts and tumours.

The results and observations of the present study show that c-Myc plays a role in the aggressive biological behaviour of odontogenic lesions like ameloblastoma and OKC. So, it can be used as a proliferative marker. However, additional immunohistochemical and DNA assays are to be carried to determine the role of c-Myc oncogene and to know if any mutations may play a role in the pathogenesis of these odontogenic lesions.