The effects of physical activity or sedentary behavior on the immune system, epigenetics, protein translation and microbiome, in relation to cancer development are under active investigation.30,31 Physical activity can reduce estradiol concentrations,32 which were positively associated with endometrial cancer risk.33 Long sitting time could increase levels of inflammatory factors, such as tumor necrosis factor-A, interleukin-6, and leptin, known risk predictors for cancer.34 This evidence concerns the gene LEP and endometrial cancer.