The Tumor Immune Microenvironment (TIME) of SCCUP in comparison to oropharyngeal carcinoma

Introduction The oncologic surgical therapy of cervical squamous cell cancer of unknown primary (SCCUP) continues to be a major challenge. The aim of this study is to highlight differences in tumor immune microenvironment (TIME) composition between SCCUP and squamous cell carcinoma of the oropharynx (OPSCC), and to derive their relevance to current treatment strategies.

Material and Methods By immunohistochemical staining, FFPE material from 50 patients with lymph node metastases of SCCUP. was analyzed for PD-L1 and p16 expression, and infiltration with CD3- and CD8-positive tumor-infiltrating lymphocytes was evaluated in 5 high-power fields. Likewise, FFPE material from 47 OPSCC patients was examined, and matched with clinicopathological data.

Results Tissue from 34 of the 50 (68.0%) SCCUP showed PD-L1 expression, whereas only 15 of the 47 (31.9%) OPSCC were PD-L1 positive. In addition, there was significantly better overall survival in the OPSCC patients (p=0.0003). In p16-negative SCCUPs, PD-L1 stratified patients with significantly higher overall and progression-free survival (p=0.0080, p=0.0002). A greater number of CD3- and CD8-positive TILs were seen in tissues from CUP patients, with no significant difference in overall and progression-free survival.

Conclusion SCCUP were shown to be immunohistochemically different from OPSCC in terms of PD-L1 expression and infiltration with tumor-infiltrating lymphocytes. Especially p16-negative patients could be additionally prognostically stratified by this. An additional significantly lower overall survival forms the basis for a study on the clinical-translational use of checkpoint inhibitor therapy in SCCUP.

Publication History

Article published online:
12 May 2023