Cancer is a symptom of abnormal cellular function that is caused by nutritional deficiencies and toxicities rather than simple genetics. Actually, only 1-2% of cancers a strictly genetic and the rest are caused by epigenetics (lack of nutrients and excessive exposure to toxic environmental chemicals). There is a lot we can do to prevent cancer from developing and Raymond explains this here and in more detail in his book, Never Fear Cancer Again.
If we can maintain normal oxygen consumption of our cells we can prevent cancers. Changing our intracellular pH from just slightly acidic to slightly alkaline can alter the oxygen delivered to our cells by more than 100 times. Lifestyle also has a great deal in causing cancer.