Background: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide and the human papillomavirus (HPV+)-driven subtype is the fastest rising cancer in North America. Although most cases of HPV+ HNSCC respond favorably to the treatment via surgery followed by radiochemotherapy, up to 20% recur with a poor prognosis. The molecular and cellular mechanisms of recurrence are not fully understood.
Methods: To gain insights into the mechanisms of recurrence and to inform patient stratification and personalized treatment, we compared the proteome and phosphoproteome of recurrent and non-recurrent tumors by quantitative mass spectrometry.
Results: We observe significant differences between the recurrent and non-recurrent tumors in cellular composition, function, and signaling. The recurrent tumors are characterized by a pro-fibrotic and immunosuppressive tumor microenvironment (TME) featuring markedly more abundant cancer-associated fibroblasts, extracellular matrix (ECM), neutrophils, and suppressive myeloid cells. Defective T cell function and increased epithelial-mesenchymal transition potential are also associated with recurrence. These cellular changes in the TME are accompanied by reprogramming of the kinome and the signaling networks that regulate the ECM, cytoskeletal reorganization, cell adhesion, neutrophil function, and coagulation.
Conclusions: In addition to providing systems-level insights into the molecular basis of recurrence, our work identifies numerous mechanism-based, candidate biomarkers and therapeutic targets that may aid future endeavors to develop prognostic biomarkers and precision-targeted treatment for recurrent HPV+ HNSCC.
Keywords: Head and neck cancer; Proteomics.
Head and neck cancer can be caused by the human papillomavirus. While this type of cancer responds well to chemotherapy given simultaneously with radiation, a significant proportion of cases recur within a few years, leading to illness and sometimes death in these patients. It is therefore important to understand the mechanisms of recurrence in order to develop better treatments. By comparing the levels of proteins and protein phosphorylation—a type of modification that affects how proteins work—between tumors from patients with or without recurrence, we found that the cells surrounding recurrent tumors show signs of fibrosis—the development of fibrous connective tissue—and suppression of the body’s immune responses. This suggests that therapies directed towards the regulators of fibrosis and immune suppression may help to overcome recurrent head and neck cancer.
© The Author(s) 2022.