There is no evidence that the SDHB gene is involved in neuroblastoma development

Neuroblastoma and pheochromocytoma have the same embryonal origin. They originate from neural crest cells, and they usually affect suprarenal glands. The SDHB gene encodes the B subunit of succinate dehydrogenase, a protein implicated in the electron transport chain and Krebs cycle. Some mutations have been described in this gene in pheochromocytoma, and this gene could be an appropriate candidate for its study in neuroblastoma given its localization in 1p35-36. The aim of this study was to analyze neuroblastoma tumors in order to assess a possible implication of this gene in neuroblastoma development. We studied 28 neuroblastoma tumor samples from different stages. Mutation research in genomic DNA was carried out after individual amplification of each of the eight SDHB exons by SSCP analysis and sequencing of those samples with migration pattern variants. No variant was found except for three polymorphisms in four neuroblastoma samples. The first polymorphism was a synonymous A-->C change in the third position of codon 6 (exon 1). The other two polymorphisms were a TTC insert at the 5' flanking intron sequence of exon 5 in a stretch of seven TTC repeats. Upon the basis of posterior microsatellite instability and hypermethylation promoter studies, which were not significant, we can conclude that the SDHB gene, a positional candidate gene, is unlikely to be related to either initiation or tumoral progression in neuroblastoma.