Renal cell carcinoma in a pediatric patient with an inherited mitochondrial mutation.

Renal cell carcinoma (RCC) is a rare pediatric renal cancer. Recent molecular genetic studies discovered a tumor-specific mutation involving translocation of a transcription factor TFE3 in a subset of pediatric RCC with distinct histopathology. We reported a case of a 2-year-old boy with RCC associated with TFE3 translocation resulting in a PRCC-TFE3 fusion gene. Interestingly, the case carried a maternally inherited mitochondrial DNA (mtDNA) alteration at the position which is usually found in MELAS (Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like Episodes) syndrome (A3243G). Although evidence of somatic alterations in mtDNA existed in various cancers, association between inherited mtDNA mutation and pediatric renal cancer has not been reported. Our case provided the first evidence of a co-occurrence between a germ line mutation in mtDNA and the somatic mutation of pediatric RCC. With this information, we speculated a role of mitochondria mutation in the pathogenesis of this cancer.