Fig. 1
From: Tumor hypoxia and role of hypoxia-inducible factor in oral cancer
 Hypoxia pathway in the presence of smoking, alcohol and HPV in HNSCC (Modified from Bredell MG, Ernst J, El-Kochairi I, Dahlem Y, Ikenberg K, Schumann DM. Current relevance of hypoxia in head and neck cancer. Oncotarget. 2016 Aug 2;7(31):50781-50804. doi: 10.18632/oncotarget.9549. PMID: 27434126; PMCID: PMC5226620. Open access CC By 4.0)