what are the causes and signs of cancer?
['Fatigue.', 'Lump or area of thickening that can be felt under the skin.', 'Weight changes, including unintended loss or gain.', "Skin changes, such as yellowing, darkening or redness of the skin, sores that won't heal, or changes to existing moles.", 'Changes in bowel or bladder habits.', 'Persistent cough or trouble breathing.']