Cell competition, apoptosis and tumour development

The phenomenon of cell competition is an interactive process originally discovered in the imaginal discs of Drosophila; it is a developmental mechanism that identifies and eliminates cells that are weaker than their neighbours or have features that make them different or not well adapted to their surroundings. It appears to be an important homeostatic mechanism to contribute to the general fitness of developing tissues. Here we discuss some of the basic features of cell competition and then focus on results indicating that cell competition is responsible for the removal of malignant or aberrant cells that may appear during development, although in certain circumstances it can revert its role to promote tumour growth. We also consider several recent studies that indicate that cell competition also occurs in vertebrates where it performs similar functions.