Cell competition possesses a cell fitness-sensing process ranging from Drosophila to mammals that selectively eliminates aberrant cells via apoptosis.The presence of cell competitive interaction will determine whether the cell contributes to the survival of organisms.Yamamoto et al.[1] recently reveal a hitherto unexplored mechanism by which the surrounding normal epithelial cells can recognize oncogenic polarity-deficient neighbors to trigger tumor-suppressive cell competition in Drosophila.