Cold Spring Harbor Laboratory Fellow Semir Beyaz and collaborators from Harvard Medical School and Massachusetts Institute of Technology have discovered that in mice, fat disrupts the relationship between intestinal cells and the immune cells that patrol them looking for emerging tumors. Reconfiguring the gut microbiome may be a way to heal the relationship.

A high-fat diet increases the incidence of colorectal cancer.

The immune system patrols tissues looking for and eliminating threats. Certain immune cells look for tags that distinguish between normal and abnormal cells. One tag, called MHC-II, helps target cells for destruction. Cell-surface MHC-II activates the immune system to destroy that cell, whether it is just worn out or about to become cancerous. Beyaz and his colleagues found that when mice ate diets high in fat, MHC-II levels were suppressed in intestinal cells. Cells with reduced levels of these tags were not recognized as abnormal and thus could grow into tumors.

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