Histologic examination of carbonic anhydrase 9 (CAIX) and hypoxia-inducible factor 1-alpha (HIF-1α), two factors that are overexpressed in hypoxic conditions, were correlated with worse outcomes and hypoxia imaging with 18F-FETNIM (fluoroerythronitroimidazole) positron emission tomography (PET) showed that tracer uptake might be predictive for treatment response in esophageal cancer [4–7]. The gene discussed is CA9; the disease is esophageal cancer.