I've heard certain foods have anticancer properties, is this true?

It is important to eat a nutritious diet that meets the body’s requirements of essential nutrients to prevent nutrient deficiencies. However, foods also provide numerous chemical constituents that may influence health and disease prevention. These components are sometimes referred to as bioactive food components. Bioactive food components exist not only naturally in foods, but also as ingredients in fortified foods and dietary supplements. When bioactive food components are put into food products they are often referred to as “functional foods”. For instance, yoghurt fortified with beneficial bacteria, or breakfast cereal fortified with antioxidants, are considered functional foods. Bioactive food components may act in many ways in the body, either directly or with other dietary constituents, to produce their favourable effect. Some examples of these components include phytochemicals, antioxidants, and omega-3 fatty acids.