Ideal lifestyles against colorectal tumorigenesis: with explanation for the impact of exercise or obesity on colorectal tumor development

Abstract

Obesity-associated cancers, including colorectal cancer, are increasing in Japan with Westernized lifestyles as exemplified by reduced physical activity and increased high-fat diet. An excessive accumulation of visceral adipose tissue causes insulin resistance, oxidative stress and adipocytokine imbalance, and these factors are suggested to be involved in colorectal tumorigenesis. In this review article, we focus on the relationships between each of the individual associated conditions, especially obesity and exercise, and colorectal tumor development with targeting molecules revealed by in vivo and in vitro studies. Furthermore, the potential for colorectal cancer prevention by targeting these molecules is discussed.