Ectonucleotidase expression on T-helper cells as a response assessment tool to immune-checkpoint therapy in head and neck cancers

• Platinum-based chemotherapy combined with cetuximab is the first line of treatment for metastatic or recurrent head and neck cancer (HNC), yet its advantages to survival are limited and its toxicity is enhanced. • With certain limits, CPS can be used as a response measure for PD-1 pathway inhibitors, which increase overall survival and safety for HNSCC patients who progress following chemotherapy. • A vital immunosuppressive route in HNSCC, the adenosinergic axis inhibits cytotoxic T-cell activity through extracellular adenosine and its receptors (A2A, A2B). • Patients with HNSCC have an accumulation of regulatory T cells (Tregs), which influence immunological responses and aid in the synthesis of adenosine by means of ectonucleotidases, so promoting immune evasion. • Treg and ectonucleotidase expression quantification in peripheral blood may function as prognostic indicators for immunotherapy response. Treatment efficacy may be increased by focusing on the adenosine pathway, with the use of adenosine receptor inhibitors.