Abstract Most cancer patients diagnosed with late-stage head and neck squamous cell carcinoma are treated with chemoradiotherapy. which can lead to toxicity. One potential alternative is tumor-limited conversion of a prodrug into its cytotoxic form. We reason this could be achieved by transient and tumor-specific expression of purine nucleoside phosphorylase (PNP). https://www.chiggate.com/aptamil-allerpro-syneo-2-900g-online-now/