Immunoexperssion of cancer stem cell marker (CD44) in ameloblastoma

BACKGROUND: Ameloblastoma is the most frequently encountered benign, locally invasive tumor. Attempts to surgically resect the tumor often leave small islands of tumor, which later result in recurrence in 50%–90% of cases. This has raised questions regarding the tumor cell populations that are responsible for tumor growth and recurrence. In ameloblastoma, whether or not cancer stem-like cells are present remains undetermined. However, if cancer stem-like cells are present in ameloblastoma, it is important to identify which type of cell possesses the stem-like characteristics and is responsible for ameloblastoma progression and recurrence. AIM: Our study aims at analyzing immunohistochemical staining to detect the expression of cancer stem cell (CSC) marker CD44 in relation to proliferative activity of tumor cells in histopathologically diagnosed cases of ameloblastoma variants and to derive a correlation between the CD44 expression and biologic behavior of the lesion. MATERIALS AND METHODS: A retrospective study, was conducted on total 25 cases ameloblastoma and were immunostained for CD44 expression. Results obtained were statistically analyzed. RESULTS: A positive correlation was observed between staining intensity of CD44 marker and the known biological behavior of the lesion. Intense staining reaction was found to be only in 8% cases, whereas 76% cases demonstrated moderate intensity and remaining 16% displayed mild immunoreactivity to CD44 marker. Staining location was more to be in stellate reticulum-like (SR-like) cells when compared to ameloblast-like (AB-like) cells. Intense immunostaining was localized in the small tumor follicles, especially in SR-like cells situated in close vicinity of peripheral AB-like cells whereas mild intensity of staining was observed in keratinizing areas. CONCLUSION: CSCs marker positive expression in benign tumor like ameloblastoma may be responsible for its aggressiveness and recurrence. CD44 marker may be of great value in predicting the biological behavior and growth potential of ameloblastoma.