Significance of PD-L1 and Tumor Microenvironment in Laryngeal Squamous Cell Cancer

Abstract

Background: Despite the considerable advancement in the field of medicine over recent decades, laryngeal cancer continues to be a challenge. The field of immune oncology has generated promising immunomodulation therapies and opened up new ways of treatment. Methods: Our retrospective study included 102 patients diagnosed with laryngeal squamous cell cancer (LSCC). Immunohistochemistry was used to evaluate the expression of PD-L1 and tumor microenvironment cells (CD4, CD8, CD68 and CD163). Results: PD-L1 expression showed statistically significant positive correlations with all examined tumor microenvironment cells. Patients with high CD68 and CD163 expression intratumorally (p = 0.0005 and p = 0.006, respectively) had statistically significant shorter disease-specific survival. Moreover, a statistically shorter time to recurrence was found in patients with high CD68 intratumoral and CD8 overall counts (p = 0.049 and p = 0.019, respectively). Also, high CD8 overall (>23%) and CD68 intratumoral (>2.7%) expression were statistically significant predictors of recurrence (p = 0.028, OR = 3.11 and p = 0.019, OR = 3.13, respectively). Conclusions: Higher CD68 and CD163 expression represented significantly worse prognosticators for clinical outcomes in patients with LSCC. In order to determine which LSCC patients will benefit from anti-PD-1/PD-L1 inhibitors, it is crucial to elucidate the relationship between PD-L1 expression, immune cell distribution and prognosis in LSCC patients.