If such tumours release insulin to the blood, it could explain the rare and unexplained occurrence of hypoglycaemic attacks described in a few patients with phaeochromocytoma (3, 4, 5, 6); in at least two of them, the hypoglycaemic attacks were hyperinsulinaemic (4, 5) and one was cured from such attacks by removal of the tumour (5). Here, INS is linked to neoplasm.