Mutation and genomic amplification of the PIK3CA proto-oncogene in pituitary adenomas
Rev. bras. pesqui. méd. biol
; Braz. j. med. biol. res;45(9): 851-855, Sept. 2012. ilus, tab
Article
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| ID: lil-646332
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BR1.1
ABSTRACT
The tumorigenesis of pituitary adenomas is poorly understood. Mutations of the PIK3CA proto-oncogene, which encodes the p110-α catalytic subunit of PI3K, have been reported in various types of human cancers regarding the role of the gene in cell proliferation and survival through activation of the PI3K/Akt signaling pathway. Only one Chinese study described somatic mutations and amplification of the PIK3CA gene in a large series of pituitary adenomas. The aim of the present study was to determine genetic alterations of PIK3CA in a second series that consisted of 33 pituitary adenomas of different subtypes diagnosed by immunohistochemistry 6 adrenocorticotropic hormone-secreting microadenomas, 5 growth hormone-secreting macroadenomas, 7 prolactin-secreting macroadenomas, and 15 nonfunctioning macroadenomas. Direct sequencing of exons 9 and 20 assessed by qPCR was employed to investigate the presence of mutations and genomic amplification defined as a copy number ≥4. Previously identified PIK3CA mutations (exon 20) were detected in four cases (12.1%). Interestingly, the Chinese study reported mutations only in invasive tumors, while we found a PIK3CA mutation in one noninvasive corticotroph microadenoma. PIK3CA amplification was observed in 21.2% (7/33) of the cases. This study demonstrates the presence of somatic mutations and amplifications of the PIK3CA gene in a second series of pituitary adenomas, corroborating the previously described involvement of the PI3K/Akt signaling pathway in the tumorigenic process of this gland.
Mots clés
Texte intégral:
1
Indice:
LILACS
Sujet Principal:
Tumeurs de l'hypophyse
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Adénomes
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Amplification de gène
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Mutation
Limites du sujet:
Adolescent
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Adult
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Aged
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Female
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Humans
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Male
langue:
En
Texte intégral:
Braz. j. med. biol. res
/
Rev. bras. pesqui. méd. biol
Thème du journal:
BIOLOGIA
/
MEDICINA
Année:
2012
Type:
Article