Expression of immunoregulatory molecules PD-L1 and PD-1 in oral cancer and precancerous lesions: A cohort study of Japanese patients

An update of knowledge on PD‐L1 in head and neck cancers: Physiologic, prognostic and therapeutic perspectives

“…Significantly higher PD‐L1 expression was observed in OSCC arising in mandibular structures or the tongue compared to the maxilla or soft palate ( p = 0.039) (Troeltzsch et al, ) and in those localized in lingual and buccal mucosa versus gingiva and floor of mouth ( p = 0.05) (Satgunaseelan et al, ). There have also been discordant results on the relationship between tumour size and PD‐L1 expression, with some studies showing no correlation (Lin et al, ; Straub et al, ) and others finding a significant relationship between PD‐L1 overexpression and tumour size (Kouketsu et al, ; Oliveira‐Costa et al, ) or the histological grade of tumours <4 cm in size (Cho et al, ).…”

“…Similarly, Chen et al found that patients with both tumour necrosis and PD‐L1 overexpression had a worse OS (Chen, Wu, et al, ). However, six studies failed to find a relationship between OS or tumour‐associated death and PD‐L1 positivity (Cho et al, ; Kouketsu et al, ; Lin et al, ; Mattox et al, ; Satgunaseelan et al, ; Troeltzsch et al, ). Furthermore, Ahn et al found a better prognosis in OSCC with both PD‐L1 overexpression and high miR‐197 levels (Ahn et al, ).…”

“…They found a significantly higher expression of PD‐L1 in OSCC than in the leukoplakias and theorized that PD‐L1 may play a role in the progression of leukoplakia to OSCC. They failed to find a significant difference in PD‐L1 expression between different grades of dysplasia (Kouketsu et al, ). Glass et al studied OSCC and oral epithelial dysplasias and found 2/12 dysplasias showed PD‐L1 staining in the epithelium (Glass, Reich, & Freedman, ).…”

Immune checkpoints indoleamine 2,3‐dioxygenase 1 and programmed death‐ligand 1 in oral mucosal dysplasia

“…There are currently several studies on the immunohistological expression of immune checkpoint molecules in oral cancer . However, less is known about the roles of these molecules in potentially malignant oral lesions.…”

“…17 There are currently several studies on the immunohistological expression of immune checkpoint molecules in oral cancer. 11,18 However, less is known about the roles of these molecules in potentially malignant oral lesions. Therefore, the purpose of this study was to analyze the expression of IDO1 and PD-L1 in oral dysplasia; to investigate the possible association between these molecules, dysplasia grade, and the inflammatory cell infiltration; and to follow disease progression and the expression of these molecules over time in oral dysplasia samples.…”