In a new study, researchers have found that consumption of high-fructose corn syrup can enhance tumor growth in mice that are genetically predisposed to develop intestinal cancer. Whether these observations with mice are relevant to the development of human intestinal cancer was not addressed in the study but is an important question for future investigation. The mouse study was prompted by human epidemiological studies that had revealed a correlation between higher intake of beverages sweetened with high-fructose corn syrup (HFCS) and obesity, and by other studies that had revealed a correlation between obesity and a higher risk of colorectal cancer (CRC). Marcus Goncalves and colleagues set out to investigate whether HFCS contributes directly to tumor development in the absence of obesity. To do this, they studied mice that were genetically predisposed to develop intestinal adenomas (benign tumors that can develop into colorectal cancer). Goncalves et al. fed the animals both moderate and large amounts of HFCS and discovered that consumption of even moderate quantities of HFCS led to dramatic increases in intestinal tumor size and grade in the mice. What's more, the results demonstrate that this increase occurred independently of the common confounding conditions of obesity and metabolic syndrome. The authors next explored the molecular mechanism underlying this effect. They found that an enzyme in the mouse tumors converts fructose into fructose-1-phosphate, which alters tumor cell metabolism, creating fatty acids that support tumor growth. If future research shows that HFCS has a similar growth-enhancing effect on human tumors, the study's findings suggest that treatments targeting fructose metabolism could provide new strategies for slowing the development and progression of colorectal cancer. In a related video, one of the study's two lead authors, Dr. Lewis Cantley, discusses the study in more detail, including its limitations. The video will be available on Monday, 18 March.