Molecular genetic analysis of FIH-1, FH, and SDHB candidate tumour suppressor genes in renal cell carcinoma.
BACKGROUND
Overexpression of the hypoxia inducible factor 1 (HIF-1) and HIF-2 transcription factors and the consequent upregulation of hypoxia inducible mRNAs is a feature of many human cancers and may be unrelated to tissue hypoxia. Thus, the VHL (von Hippel-Lindau) tumour suppressor gene (TSG) regulates HIF-1 and HIF-2 expression in normoxia by targeting the alpha subunits for ubiquitination and proteolysis. Inactivation of the VHL TSG in VHL tumours and in sporadic clear cell renal cell carcinoma (RCC) results in overexpression of HIF-1 and HIF-2. However, RCC without VHL inactivation may demonstrate HIF upregulation, suggesting that VHL independent pathways for HIF activation also exist. In RCC, three candidate HIF activating genes exist-FIH-1 (factor inhibiting HIF), SDHB, and FH-which may be dependent or independent of VHL inactivation.


OBJECTIVE
To investigate FIH-1, SDHB, and FH for somatic mutations in sporadic RCC.


METHODS
Gene mutation was analysed in primary RCCs (clear cell RCCs, papillary RCCs, and oncocytomas) and RCC cell lines. SDHB mutation analysis was performed by denaturing high performance liquid chromatography followed by direct sequencing of aberrant PCR products. FH and FIH-1 mutation analysis were performed by single stranded conformational polymorphism and direct sequencing of PCR products.


RESULTS
No mutations were identified in the three genes investigated.


CONCLUSIONS
There was no evidence to suggest that somatic mutations occur in the FH, FIH-1, or SDHB TSGs in sporadic RCCs.
Morris
M R
MR
Section of Medical and Molecular Genetics, Department of Paediatrics and Child Health, University of Birmingham, the Medical School, Birmingham B15 2TT, UK.
Maina
E
E
Morgan
N V
NV
Gentle
D
D
Astuti
D
D
Moch
H
H
Kishida
T
T
Yao
M
M
Schraml
P
P
Richards
F M
FM
Latif
F
F
Maher
E R
ER
D001483:Base Sequence; D002292:Carcinoma, Renal Cell / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods; D004273:DNA, Neoplasm / Q000235:genetics; D005649:Fumarate Hydratase / Q000235:genetics; D016147:Genes, Tumor Suppressor; D006801:Humans; D007506:Iron-Sulfur Proteins; D007680:Kidney Neoplasms / Q000235:genetics*; D019656:Loss of Heterozygosity; D006899:Mixed Function Oxygenases; D008969:Molecular Sequence Data; D009154:Mutation; D018807:Polymorphism, Single-Stranded Conformational; D021122:Protein Subunits / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D013385:Succinate Dehydrogenase / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm; D007506:Iron-Sulfur Proteins; D021122:Protein Subunits; D012097:Repressor Proteins; D014157:Transcription Factors; D006899:Mixed Function Oxygenases; C439790:HIF1AN protein, human; C108095:SDHB protein, human; D013385:Succinate Dehydrogenase; D005649:Fumarate Hydratase