Loss of apico-basal polarity is one of the crucial factors that drives epithelial tumor progression,scribble/discs large/lethal giant larvae (scrib/dlg/lgl),a group of apico-basal polarity genes,were initially identified as members of“neoplastic”tumor-suppressors in flies.The components of the Hippo signaling pathway,which is crucial for organ size control and cancer development,were also identified through Drosophila genetic screens as members of“hyperplastic”tumor-suppressors.Accumulating evidence in recent studies implies that these two tumor-suppressor signaling pathways are not mutually exclusive but rather cooperatively act to give rise to highly malignant tumors.The interaction of these tumor-suppressor pathways could include deregulations of actin cytoskeleton,cell—cell contact,and apical-domain size of the epithelial cell. Loss of apico-basal polarity is one of the crucial factors that drives epithelial tumor progression, scribble / discs large / lethal giant larvae (scrib / dlg / lgl), a group of apico-basal polarity genes, were initially identified as members of “neoplastic ” tumor-suppressors in flies. components of the Hippo signaling pathway, which is crucial for organ size control and cancer development, were also identified through Drosophila genetic screens as members of “hyperplastic ” tumor-suppressors. in recent studies implies that these two tumor-suppressor signaling pathways are not mutually exclusive but rather cooperatively act to give rise to highly malignant tumors. The interaction of these tumor-suppressor pathways could include deregulations of actin cytoskeleton, cell-cell contact, and apical -domain size of the epithelial cell.