Onkologie. 2026:20(4):253-257 | DOI: 10.36290/xon.2026.045

PD-L1 expression status in head and neck carcinomas - a topic review and the results of own study

Vladimír Bartoš¹, Katarína Janíková¹, Michal Urda², Anna Farkašová¹

¹ Martinské bioptické centrum, s. r. o., Martin

² Oddelenie pneumológie a ftizeológie, Fakultná nemocnica s poliklinikou F. D. Roosevelta, Banská Bystrica

In head and neck cancers, PD-L1 protein expression in tumor tissue is a key predictive parameter that helps determine which patients will respond best to treatment with checkpoint inhibitors. PD-L1 status is standardly determined using the combined positive score (CPS). CPS ≥ 1 is a prerequisite for the use of pembrolizumab with chemotherapy in the first-line treatment of unresectable, recurrent and/or metastatic disease. In CPS ≥ 20, first-line treatment with pembrolizumab as a single agent may be considered. Previous studies on head and neck cancers have reported diverse conclusions regarding the prevalence of PD-L1-positive tumors and associated clinicopathological indicators. This paper provides a comprehensive review of the issue, that is supplemented by the results of the authors' own observations. In their cohort of 208 patients with head and neck cancers who had PD-L1 expression investigated by immunohistochemistry, the PD-L1-positive cancers accounted for 84.6% of cases. They confirmed 32 tumors (15.4%) with negative PD-L1 status (CPS < 1), 91 tumors (43.7%) with low PD-L1 positivity (CPS ≥ 1 and < 20), and 85 tumors (40.9%) with high PD-L1 positivity (CPS ≥ 20). The results indicate, the vast majority of head and neck cancers display a positive PD-L1 status. However, the level of PD-L1 expression alone does not always correlate with the response to inhibitor treatment, which is due to temporal and spatial heterogeneity. In particular, an examination from a small biopsy sample may not correspond to the overall biological profile of the tumor. Sampling from multiple sites and analyzing samples with respect to deep invasive tumor margins should be optimal. If the result is negative or borderline, in case of clinical doubt, it is recommended to consider re-biopsy.

Keywords: head and neck cancers, PD-L1, combined positive score, pembrolizumab, heterogeneity.

Accepted: September 21, 2026; Published: October 9, 2026  Show citation