Differential gene expression in pituitary adenomas by oligonucleotide array analysis.
OBJECTIVE
Microarray technology allows for the expression profile of many thousands of genes to be quantified at the same time, and has resulted in novel discoveries about the tumour biology of a number of cancers. We sought to do this in pituitary adenomas, the most common intracranial neoplasm.


METHODS
Affymetrix GeneChip HG-U133A oligonucleotide arrays covering 14 500 well-characterised genes from the human genome were used to study pooled RNA for each of the four major pituitary adenoma subtypes. Individual gene-expression levels in the tumours were compared relative to the expression profile in normal pooled pituitary RNA. Three differentially expressed genes with potential importance in tumourigenesis were chosen for validation by real-time quantitative PCR on the original tumours and on an additional 26 adenomas.


RESULTS
Bioinformatic analysis showed that 3906 genes and 351 expressed sequence tags were differentially expressed among all pituitary tumour subtypes. Lysosomal-associated protein transmembrane- 4-beta (LAPTM4B), a novel gene upregulated in hepatocellular carcinoma, was significantly over-expressed in adrenocorticotrophin (ACTH)-secreting adenomas and non-functioning pituitary adenomas (NFPAs). Bcl-2-associated athanogene (BAG1), an anti-apoptotic protein found at high levels in a number of human cancers, was significantly over-expressed in growth hormone-secreting and prolactin-secreting adenomas and NFPAs. The cyclin-dependent kinase inhibitor p18, in which murine gene deletion has been shown to produce pituitary ACTH cell hyperplasia and adenomas, was significantly under-expressed in ACTH-secreting adenomas.


CONCLUSIONS
Expression array analysis of pituitary adenomas using the Affymetrix GeneChip HG-U133A arrays appears to be a valid method of identifying genes that may be important in tumour pathogenesis.
Department of Endocrinology, St Bartholomew's and the Royal London School of Medicine and Dentistry, London, UK.
Damian G
DG
Morris
Mädälina
M
Musat
Sándor
S
Czirják
Zoltán
Z
Hanzély
Debra M
DM
Lillington
Márta
M
Korbonits
Ashley B
AB
Grossman
D000236:Adenoma / Q000235:genetics* / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics; D050763:Cyclin-Dependent Kinase Inhibitor p18; D004268:DNA-Binding Proteins; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D015513:Oncogene Proteins / Q000235:genetics; D010911:Pituitary Neoplasms / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011388:Prolactin / Q000378:metabolism; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins / Q000235:genetics
C091732:BCL2-associated athanogene 1 protein; C493971:CDKN2C protein, human; D018797:Cell Cycle Proteins; D050763:Cyclin-Dependent Kinase Inhibitor p18; D004268:DNA-Binding Proteins; C477083:LAPTM4B protein, human; D008565:Membrane Proteins; D015513:Oncogene Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D000324:Adrenocorticotropic Hormone; D011388:Prolactin