AUTHOR=Hanroongsri Jaruwat , Amornphimoltham Panomwat , Younis Rania H. , Chaisuparat Risa 

TITLE=Expression of PD-L1 and p-RPS6 in epithelial dysplasia and squamous cell carcinoma of the oral cavity

JOURNAL=Frontiers in Oral Health

VOLUME=5

YEAR=2024

URL=https://www.frontiersin.org/journals/oral-health/articles/10.3389/froh.2024.1337582

DOI=10.3389/froh.2024.1337582

ISSN=2673-4842

ABSTRACT=<sec><title>Introduction</title><p>Oral squamous cell carcinoma (OSCC) is often preceded by oral epithelial dysplasia (OED). The role of ribosomal protein S6 (RPS6) and programmed cell death ligand-1 (PD-L1) in the progression of OED to OSCC remains unclear. This study aimed to investigate the expression of phosphorylated RPS6 (p-RPS6) and PD-L1 in OSCC and OED and to examine its relationship with clinicopathological features.</p></sec><sec><title>Methods</title><p>Fifty-two OSCC and 48 OED cases were recruited for immunohistochemical analysis of p-RPS6 and PD-L1 expression. The expression of markers was correlated with clinicopathological features of OSCC and OED.</p></sec><sec><title>Results</title><p>We found p-RPS6 expression in all cases of OSCC and OED, whereas PD-L1 was expressed in 42/48 (87%) OED and in 28/52 (53%) OSCC. The patients with mild OED presented higher expression level of PD-L1 and p-RPS6 significantly, when compared to moderate-differentiated OSCC patients (<italic>p</italic> &lt; 0.05). Moreover, we found a significant positive correlation between PD-L1 and p-RPS6 expression in OED and OSCC patients (<italic>p</italic> &lt; 0.01). The PD-L1 expression was significantly related to more than 2 cm tumor size in OSCC patients (<italic>p </italic>=<italic> </italic>0.007).</p></sec><sec><title>Discussion</title><p>Our findings suggest the upregulation of PD-L1 may be related with activation of the mTOR pathway in the early events of tumor progression and the pathogenesis of OSCC.</p></sec>