HPRT1 and head and neck squamous cell carcinoma: HPRT1, which plays a central role in the generation of purine nucleotides through the purine salvage pathway, has been identified as an unfavourable prognostic marker in many cancers, including HNSCC.33 TBPL1 encodes a member of the TATA box-binding protein family, activating the transcription of metabolic genes.