Non-surgical management of Ameloblastoma: A proof of concept study exploring the immunohistochemical expression of immune checkpoint Programmed Death Ligand- 1 in Ameloblastoma.

OBJECTIVES

Ameloblastoma (AM) is the most common odontogenic tumour. Non-surgical and conservative treatment approaches are rising in popularity which traditionally involve segmental jaw resection with wide margins. The current study aims to assess the immunohistochemical expression of immune checkpoint Programmed death ligand - 1 (PDL-1) in AM when compared to normal dental follicle (DF).

METHODS

Immunohistochemical staining of AM (n = 25) and DF (n = 12) using PDL-1 antibody was performed on tissue blocks retrieved retrospectively from the archives. The PDL-1 Total Positive Score (TPS), staining intensity score and H score were calculated. These were statistically compared and p value ≤ 0.05 was considered significant.

RESULTS

We observed statistically significant increase in the expression of PDL-1 in AM (80 %) when compared to DF (58.4 %) in terms of TPS score (p < 0.001), H score (p = 0.022) and staining intensity (p < 0.001). PDL-1 positivity was seen in both peripheral and central odontogenic epithelial tumour cells with increased staining in the stellate reticulum like areas.

CONCLUSIONS

This study highlights the evidence of immune checkpoint alteration in AM which is a benign but aggressive odontogenic neoplasm. The preliminary results encourage more research in the terrain of immunotherapy for odontogenic neoplasms.