New research in The Journal of Immunology uncovers how high blood sugar (hyperglycemia) and type 1 diabetes (T1D) may protect against certain cancers like melanoma, breast and colon cancer. T1D has been associated with a decreased risk of certain cancers, but the exact reasons why have remained a mystery. New data from studies in mice now show that it could be due to changes in immune cells, called T cells, caused by hyperglycemia.