IMR Press / FBE / Volume 3 / Issue 1 / DOI: 10.2741/E247

Frontiers in Bioscience-Elite (FBE) is published by IMR Press from Volume 13 Issue 2 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on as a courtesy and upon agreement with Frontiers in Bioscience.

Respiratory chain complex I is a mitochondrial tumor suppressor of oncocytic tumors
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1 Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Austria
2 Department of Pathology, University Hospital Salzburg, Paracelsus Medical University, Austria
3 Institute of Pathology, Medical University of Graz, Austria
4 Biobank, Medical University of Graz, Austria

*Author to whom correspondence should be addressed.

Academic Editor: Anna Czarnecka

Front. Biosci. (Elite Ed) 2011, 3(1), 315–325;
Published: 1 January 2011
(This article belongs to the Special Issue Frontiers in molecular medicine)

Oncocytic tumors, also called oxyphilic tumors, are characterized by hyperproliferation of mitochondria, which histologically presents as a fine granular eosinophilic cytoplasm. In accordance with the high mitochondrial density in oncocytomas, transcript levels of subunits of complexes of the oxidative phosphorylation (OXPHOS) system are increased. Hence, for a long time oncocytomas were presumed to have a highly active aerobic mitochondrial energy metabolism. Recently, detailed analysis of all OXPHOS complexes in a variety of oncocytomas revealed loss of complex I and compensatory up-regulation of the other complexes. In half of the oncocytoma cases examined the absence of complex I is caused by disruptive mutations in mitochondrial DNA encoding complex I subunits. The new data presented here on rare oncocytomas and the accompanying review of the literature clearly indicate that complex I deficiency in combination with up-regulation of mitochondria can be regarded as a hallmark of oncocytic tumor cells. Therefore, complex I of the respiratory chain has to be added to the growing list of mitochondrial tumor suppressors.

Respiratory Chain Complex I
Oncocytic Tumors
Respiratory Chain
Warburg Effect
Mitochondrial DNA
Tumor Suppressor
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