Human Heredity 11th Edition by Michael Cummings

Exercise 18

Studies have shown that there are significant differences in cancer rates among different ethnic groups. For example, the Japanese have very high rates of colon cancer but very low rates of breast cancer. It has also been demonstrated that when members of low-risk ethnic groups move to high-risk areas, their cancer risks rise to those of the high-risk area. For example, Japanese who live in the United States, where the risk of breast cancer is high, have higher rates of breast cancer than do Japanese who live in Japan. What are some of the possible explanations for this phenomenon? What factors may explain why the Japanese have higher rates of colon cancer than do other ethnic groups?