Role of obesity in the tumorigenesis of gastric cancer

Gastric cancer as a common cancer is a multi-factorial disease that is dependent on parallel effects of environment and genetics. Endogenous and host factors, including gender and several genetic backgrounds are known risk factors also many environmental factors, including smoking, diet, infection and increasing body weight and body mass index (BMI) are associated with the gastric cancer. Epidemiological data have consistently demonstrated a positive relation between obesity and gastric cancer, whereas mechanistic studies have sought to uncover obesity related carcinogenic pathways. Biological mechanisms and the relationship between obesity and cancer are complex and not well understood. Different effective factors include obesity-related hormones and adipokines, growth factors, modulation of energy balance and calorie restriction, inflammatory processes and multiple signaling pathways that affect cancer cell promotion and progression. In this review, we will discuss the recent advances in the understanding of the association of obesity changes in the gastric cancer.