Dynamic contrast‑enhanced MRI as a predictor of programmed death ligand‑1 expression in patients with Oral Squamous Cell Carcinoma

Immune checkpoint inhibitors (ICIs) targeting programmed death ligand‑1 (PD‑L1) are highly promising therapies for oral squamous cell carcinoma (OSCC). The assessment of PD‑L1 expression may help predicting the therapeutic effect of ICIs and, thus, benefit patient selec‑ tion. Contrast index (CI) parameters derived from dynamic contrast‑enhanced magnetic resonance imaging (DCE‑MRI) have been proven as efficient to assess microvessel density (MVD) in OSCC. The present study aimed to determine the correlation between DCE‑MRI parameters and MVD and between DCE‑MRI parameters and PD‑L1 expression to determine whether DCE‑MRI could be used non‑invasively to evaluate PD‑L1 expression in patients with OSCC. A total of 21 patients with primary OSCC who had undergone a 3T MRI scan, including DCE‑MRI, were included in the present study, and CI curve‑derived parameters were examined. The MVD and PD‑L1 expression in the surgically resected specimens were analyzed using immunohistochemistry (IHC) staining for CD31 and IHC staining for PD‑L1, respectively. The results demonstrated that the expression levels of these markers were correlated with DCE‑MRI parameters. PD‑L1 expres‑ sion levels were found to be significantly correlated with the maximum CI (CI‑max; P=0.007), peak CI (CI‑peak; P=0.007), maximum CI gain (CI‑gain; P=0.006) and MVD (P=0.001) values. The mean CI‑max, CI‑peak, CI‑gain and MVD values were significantly higher in tumors with high PD‑L1 expression (P<0.05). MVD levels were also significantly correlated with the time of CI‑max (T‑max; P=0.003) and CI‑gain (P=0.037). The mean CI‑gain was significantly increased, and the mean T‑max was significantly shorter in high MVD tumors (P<0.05 and P<0.01, respectively). In summary, the findings from the present study confirmed the correlation between CI param‑ eters, derived from DCE‑MRI, and MVD, and suggested that these parameters may be correlated with PD‑L1 expression in OSCC tumor cells.