GCG and neoplasm: • Genetic biomarkers    ∘Menin    ∘RET    ∘ VHL    ∘ JAK3    ∘ NRAS    ∘ RB1    ∘ VHL1• Ki-67• Chromogranin A (CgA)• 5-Hydroxyindoleacetic acid (5-HIAA)• Mammalian target of rapamycin (mTOR)• CDKN1B (p27)• Circulating tumor cells (CTC)• Hormonal markers    ∘ Insulin    ∘ Gastrin    ∘ Glucagon    ∘ Somatostatin    ∘ Growth hormone    ∘ Calcitonin    ∘ Substance P    ∘ Pancreastatin