[Apoptosis and its importance in the development and therapy of tumors (review)].

This review focuses on apoptosis and its regulation as a tool of principal control mechanism of tissue homeostasis. Defects in regulation of apoptosis contribute to a various pathological processes, including tumor development, chronic inflammatory diseases, immunological disorders and many others. Apoptosis influences sensitivity to radiotherapy and chemotherapy of tumours. Microscopically the apoptosis is characterized by morphological changes, which result in the formation of apoptotic bodies. Apoptosis is an active process, which require synthesis and activation of a set of the specific cellular proteins. Among them, the key role belongs to the family of cystein proteases--caspases activated either through the death receptors or via activation steps starting with the release of a mitochondrial cytochrome c. Activation of caspases promotes the activation of downstream effectors leading to the cleavage of target cellular proteins and genomic DNA. The members of Bcl-2 family and p53 are- the others important proteins influencing the regulation of apoptosis. Enhancing of our knowledge about apoptosis and its mechanisms highly improves the rationale for diagnostics and therapy in oncology.