Endogenous hyperinsulinemia has been proposed as one of the causal factors contributing to the association between obesity, diabetes, and increased cancer risk and mortality. Previous studies have examined the mechanisms through which hyperinsulinemia promotes cancer progression, but it is not understood how hyperinsulinemia contributes to cancer incidence. Disruption of cell polarity is an early event in epithelial cancers, and cells that lose polarity are usually eliminated through tumor-suppressive cell competition. Sanaki and colleagues used Drosophila with scrib (scribble planar cell polarity protein) mutant cell clones in the eye disc to understand the mechanisms underlying tumor-suppressive cell competition. They discovered that hyperinsulinemia gives epithelial cancer cells a competitive advantage.