Meeting report: cellular dependence--old concept, new mechanisms.

Programmed cell death occurs in response to both the presence of various extracellular factors and the lack of specific factors. Receptors that can mediate cell death in the absence of ligand binding are called dependence receptors, and they were the topic of the meeting held during the summer of 2003 in Fondation des Treilles, France. Not only is progress being made in the identification of new dependence receptors, but the partners that carry out this "negative" signal are also coming to light. With several of the receptors implicated in various human developmental disorders or disease states, gaining an understanding of the molecular mechanisms controlling dependence receptor-mediated cell death has clear clinical relevance.