Background
Head and neck squamous cell carcinoma (HNSCC) is a type of cancer that originates in various anatomical regions of the head and neck and is typically diagnosed as an advanced disease. Immunotherapy has shown promising results for patients with recurrent or metastatic (R/M) disease, but only a small percentage of patients benefit from the treatment. Therefore, novel predictive biomarkers of therapy response or resistance are required.
Methods
In this retrospective study, 21 formalin-fixed paraffin-embedded (FFPE) tissue samples from immunotherapy-treated patients were collected at the Royal Brisbane and Women’s Hospital (RBWH). Spatially resolved tissue compartment-specific analyses of protein biomarkers were done by a 78-plex immune-oncology panel, including cell death, immune activation status, immune cell typing, immune cell profiling, PI3K/AKT signalling, Pan-tumour, and IO drug target panels, using Nanostring Digital Spatial Profiler (DSP). Survival analyses based on Response Evaluation Criteria in Solid tumours (RECIST) were performed against tissue compartment-specific protein expression.
Results
Our data unravelled significant differentially expressed proteins in tumour and stromal regions in patients with partial response (PR) versus those with progressive disease (PD). In the tumour compartment, patients with PR had a higher expression of a couple of protein biomarkers, such as PD-1, PD-L1, and CD68, while patients with PD showed higher expression levels of VISTA and CD66b. In the stromal compartment, patients with PR had a higher expression of PD-1, PD-L1, ER-alpha, HLA-DR, and CD68, while those with PD had overexpression of VISTA, BIM, BAD, and CD44.
Conclusion
In our data, significant protein signatures were found to be similar in both the tumour and the tumour microenvironment (TME) of patients with PR versus patients with PD. Together, this study highlights the utility of spatial proteomics for delineating the tumor microenvironment composition in HNSCC.