Endogenous potential hypoxia biomarkers include HIF, erythropoietin EPO, CAIX, glucose transporter GLUT-1/3, etc. Fluoro18 misonidazole positron emission tomography ([18F]FMISO PET) is a common tool used as a non-invasive imaging technique to assess tumor hypoxia (26). Here, EPO is linked to neoplasm.