Predictive value of CD8/FOXP3 ratio combined with PD-L1 expression for radiosensitivity in patients with squamous cell carcinoma of the larynx receiving definitive radiation therapy.

Abstract

Little is known about immune-related radiosensitivity in patients with squamous cell carcinoma of the larynx (SCC-L) treated with radiation therapy (RT). We retrospectively reviewed 91 patients with SCC-L treated with RT or chemoradiation therapy and performed immunohistochemical examination to analyze PD-L1 level on tumor cells, CD4⁺ tumor-infiltrating lymphocytes (TILs), CD8⁺ TIL, and FOXP3⁺ TIL using pretreated biopsy specimens. The association between these immune-related parameters and radiosensitivity was evaluated. Multivariate analyses showed that high CD8/FOXP3 ratio combined with negative PD-L1 expression was an independent and significant favorable predictive factor for local control, compared with the other groups. We showed that high CD8/FOXP3 ratio combined with negative PD-L1 expression might be a useful biomarker of radiosensitivity in patients with SCC-L receiving definitive RT. We propose that coassessment of CD8/FOXP3 ratio and PD-L1 expression level in tumor cells can help predict potential radiosensitivity in patients with SCC-L.