CA9 and neoplasm: In another study of 27 NET patients, SUVmax on FDG-PET correlated with greater tumor size, higher expression of Ki-67, and lower expression of the Von Hippel Lindau gene, whose inactivation leads to the accumulation of the hypoxia-inducible factor protein and “pseudohypoxic” state with enhanced transcription of specific target genes, such as CA9 and GLUT1 (p = 0.03, 0.004 and 0.008, respectively) [108].