The correlation between BxPC3 cell 5xHRE/GFP expression and other known biomarkers of tumor hypoxia [pimonidazole and carbonic anhydrase IX (PIMO and CA9, respectively)] was assessed using 10 different ex vivo tumor samples, each serially sectioned (5 μm thick) and immunofluorescence-stained against GFP, PIMO, and CA9 (Fig. 6A). The gene discussed is CA9; the disease is neoplasm.