How would you know if you have cancer? is there any signs? would a blood test show if you hsve cancer?

No: Cancer is not one disease, but there are multiple types of cancers that affect multiple organs. There is no blood test for a generic diagnosis of cancer. The signs and symptoms of different cancers vary and there is no pathognomnic sign or symptom either. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex.