The MEN2B mutation causes aggressive malignant tumors in the thyroid gland during early childhood and later-appearing tumors in the adrenal glands (pheochromocytoma) as well as other kinds of abnormal growths [2], [44] but testis cancer has not been reported as a feature of men with the disease ([2] updated 5/4/2010). The gene discussed is RET; the disease is pheochromocytoma.