CELLULAR ALTERATIONS IN PITUITARY-TUMORS

Citation
A. Spada et al., CELLULAR ALTERATIONS IN PITUITARY-TUMORS, European journal of endocrinology, 130(1), 1994, pp. 43-52
Citations number
102
Categorie Soggetti
Endocrynology & Metabolism
ISSN journal
08044643
Volume
130
Issue
1
Year of publication
1994
Pages
43 - 52
Database
ISI
SICI code
0804-4643(1994)130:1<43:CAIP>2.0.ZU;2-6
Abstract
In the last few years, molecular studies on pituitary adenomas have yi elded evidence supporting a primary pituitary origin of these tumors. Although the existence of genomic alterations in tumoral cells is stro ngly suggested by the fact that almost all pituitary adenomas are mono clonal in origin, structural genetic abnormalities such as rearrangeme nt, deletion or mutation, which could result in transcriptional activa tion, have been identified in a minority of tumors. As far as the poss ible loss of anti-oncogenes in pituitary tumors is concerned, gene alt erations have not been found in the p53 nor in the retinoblastoma gene , while loss of chromosome 11q13 sequences, which contain the deduced location of the yet uncloned MEN-1 gene, has been reported in a subset of GH-secreting adenomas. With regard to the activation of dominant o ncogenes in the process of tumor formation, activating mutations of ei ther the Gs alpha-subunit or the ras gene have been identified in a la rge proportion of GH-secreting adenomas and in individual particularly invasive tumours, respectively. Promoting agents such as hypothalamic neurohormones and growth factors may be required for the selective gr owth of genetically altered cells. In this respect, it is worth noting that receptor/postreceptor alterations occurring in pituitary tumors may cause an increased action of stimulatory neurohormones with growth promoting properties as well as defective action of inhibitory inputs .