Tissue specificity of apoptotic signal transduction.

Two major apoptotic pathways exist in mammalian cells: the death receptor and mitochondrial pathways. The cross talk between these two pathways is minimal, and they operate basically independent of each other under physiological conditions. Therefore, the tissue specificity of the signal pathway during apoptosis is observed in various tissues and organs. In this article, I demonstrate several examples of apoptosis induced by different signal pathways: apoptosis of human amniotic epithelial cells upon fetal membrane rupture induced by the death receptor pathway, apoptosis of human endometrial cells shed via menstruation and in the selection of B cells in gut-associated lymphoid tissues induced by both the death receptor and mitochondrial pathways, and apoptosis of lovastatin-induced breast cancer cells induced by the mitochondrial pathway.