There is evidence that avocados may prevent cancer. Prostate cancer cells are slowing down in the lab when avocados are consumed. As well as reducing chemotherapy side effects, they seem to enhance the effectiveness of the treatment. It might just be that antioxidants and healthy fats can help you fight cancer and chemotherapy side effects, even though they have only been tested in test tubes.
Additionally, lutein and zeaxanthin may protect your skin from UV rays (but you still need sunscreen!) and may repair damage.