Following PDGFRβ, carbonic anhydrase 9, Ki-67, VEGFR2 and p-AKT as potential biomarkers by immunohistochemistry, they found that sunitinib displayed a greater activity in grade 3 gastro-entero-pancreatic neuroendocrine tumors with low Ki-67 and a lower one when p-AKT expression was high [64]. Here, MKI67 is linked to pancreatic neuroendocrine tumor.