Study on the Gene Expression Profile and Molecular Mechanism of Pituitary Tumors

Objective To study the gene expression profile and molecular mechamism of pituitary tumors. Methods cDNA libraries of the non functional pituitary tumor (NFPT) and GH -- producing adenoma (GHPA) were constructed. Large -- scale sequencing and bioinformatics were used. Results 1253 and 603 ESTs of good quality were produced from NFPT and GHPA cDNA libraries respectively. The categories of genes most highly expressed in these pituitary tumors were those participating in gene/protein expression (29% and 28% from NFPT and GHPA respectively), and the next were those related with metabolism (18% and 21% from NFPT and GHPA, respectively). Compared with ESTs data from the normal pituitary, the expressions of these two categories of genes were higher in pituitary tumors. The FSH β subunit gene is expressed in NFPT, while the GH and PRL gene in GHPA. Comparing the gene expression profiles of these libraries, we found that the expression of GSa gene was higher than that of calmodulin in GH -- producing adenoma and the normal pituitary, but the reverse occurred in the non functional pituitary tumor. By electronic hybridization, we found some genes in the category related with cell division, which were expressed in the pituitary tumor, but not in the normal pituitary, and some of those were found to be involved in tumorigenesis. 74 ESTs representing new genes were only expressed in the pituitary tumor but not in the normal pituitary. Conclusion The gene expression profile study suggested that the metabolism and the gene/protein expression are more active in pituitary tumors than in the normal pituitary. The main signal transduction pathway may be different in various pituitary tumors. By comparing three libraries, it was found that the expression of some genes involved in cell division is different in NFPT or GHPA from that in the normal pituitary.