High glucagon levels (diagnostic when blood glucagon levels are >500pg/ml) (67) secreted by the tumour are associated with some specific and non-specific comorbidities including necrolytic migratory erythema (55-90%), weight loss (60-90%), DM or glucose intolerance (30-90%), mucosal lesion (glossitis, cheilitis, stomatitis) (30-40%), diarrhoea (10-15%), anaemia (30-80%), hypo aminoacidemia, low zinc levels, deep vein thrombosis (50%) and depression (50%) (66, 69, 70). The gene discussed is GCG; the disease is major depressive disorder.