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

Abstract

Immune checkpoint molecules IDO1 and PD-L1 are modulated during oral epithelial dysplastic changes, and their expression is associated with inflammatory cell infiltration in the lamina propria. As immune checkpoint molecules expression fluctuates over time, these molecules are not useful as biomarkers for oral mucosal dysplasia progression.

Prevalence of PD‐L1 expression in head and neck squamous precancerous lesions: a systematic review and meta‐analysis

“…However, one must also take into consideration that sample sizes may be too small to highlight a strong difference. 26,33 Notwithstanding these caveats, perhaps these findings can suggest a pathway for this biological process. Further studies with a larger sample size are needed to refine the evaluation of PD-L1 expression in precancerous lesions.…”

“…The studies included in this systematic review involved patients with potentially malignant squamous lesions from Asia, [25][26][27][28][29][30][31][32] Europe, 33,34 South America, 35,36 and North America. 37,38 Two of the included studies were represented by abstracts only.…”

“…37,38 Two of the included studies were represented by abstracts only. 37,38 The type of premalignant lesions in studies varied: eight studies dealt with oral dysplasia lesions, [27][28][29][30][31][32][33]38 three studies considered oral leukoplakia with or without dysplasia, 25,34,35 two studies used the broad terminology of "oral epithelial premalignant lesion," 26,37 and one focused on actinic cheilitis. 36 The prevalence of PD-L1 expression was one of the main aims of the study in nine publications, 25,26,30,[33][34][35][36][37][38] while in the remaining studies the main outcome was the expression of other markers of the immunological microenvironment and their correlation with PD-L1 among other molecules.…”

“…Pooling data from nine studies, 25,26,30,[33][34][35][36][37][38] the pooled prevalence of PD-L1 positivity in precancerous lesions of the head and neck was 48.25% (CI 21.07-75.98) with high heterogeneity (I 2 98%, tau2 0.1797, P < .01; Figure 2). The pooled prevalence of PD-L1 positivity was recalculated after removal of an outlier study (the study by Gonçalves et al 35 ) which was individuated with the assessment of studentized residuals, but high heterogeneity remained (pooled estimate 38.34%, CI 19.17-59.48, I 2 95%, tau2 0.0822, P < .01).…”

“…The pooled estimate was 45.04% (CI 7.39-86.30, I 2 98%, tau2 0.2936) ( Figure 3). Six studies 25,26,[33][34][35][36] allowed comparison of PD-L1 expression in premalignant lesions to normal mucosa. Pooled RR of PD-L1 positivity was 1.65 (CI 0.65-4.03, P = .30) showing a tendency to higher positivity rate in precancerous lesions, but without reaching statistical significance and with high heterogeneity (I 2 91%, tau2 0.82) (Figure 4).…”