[Paraganglioma in the area of the head and neck. A review of molecular genetic research].

Paragangliomas of the head and neck region are usually benign tumors that develop from chemoreceptors of paraganglionic origin in the majority of patients. These receptors play an important role in sensing and regulation of the blood CO(2) level. Genetic alterations in the mitochondrial enzyme complex II (SDH), which is involved in respiratory chain and citric acid cycle reactions, have been shown to lead to sporadic as well as familial cases of these tumors. The gene encoding the subunit SDHD shows mutations in up to 50% of these cases. In addition, loss of heterozygosity (LOH) was demonstrated in these tumor samples and has been shown to be connected with oncogenesis of paragangliomas. Thus, SDHD is the first known tumor suppressor gene encoding a mitochondrial protein. In this article we summarize the current state of knowledge concerning the development of paragangliomas.