RESUMO
CONTEXT: Genetic aberration in phosphatidylinositol 3-kinase (PI3K)/AKT pathway has been detected in numerous and diverse human cancers. PIK3CA, which encodes for the catalytic subunit of p110alpha of PI3K, is amplified in some cases of papillary thyroid cancer (PTC). Mutations in the PIK3CA have also been identified in thyroid cancers and, although relatively common in anaplastic thyroid carcinoma, are uncommon in PTC. OBJECTIVE: The objective of the study was to investigate genetic alterations like PIK3CA gene mutation, PIK3CA amplification, RAS, and RAF mutations and to further explore the relationship of these genetic alterations with various clinicopathological characteristics in Middle Eastern PTC. DESIGN: We used the fluorescence in situ hybridization technique for analysis of PIK3CA amplification from 536 PTC cases, and selected amplified samples were further validated by real-time quantitative PCR. Mutation analysis was done by direct DNA sequencing of PIK3CA, N2-RAS, and BRAF genes. RESULTS: PIK3CA amplification was seen in 265 of 499 PTC cases analyzed (53.1%); PIK3CA gene mutations in four of 207 PTC (1.9%); N2-RAS mutations in 16 of 265 PTC (6%); and BRAF mutations in 153 of 296 PTC (51.7%). N-RAS mutations were-associated with an early stage (P = 0.0465) and lower incidence of extrathyroidal extension (P = 0.027), whereas BRAF mutations were-associated with metastasis (P = 0.0274) and poor disease-free survival (P = 0.0121) in PTCs. CONCLUSION: A higher incidence of PIK3CA alterations and the possible synergistic effect of PIK3CA alterations and BRAF mutations suggest their major role in Middle Eastern PTC tumorigenesis and argue for therapeutic targeting of PI3K/AKT and MAPK pathways.
Assuntos
Carcinoma Papilar/genética , Carcinoma Papilar/patologia , Fosfatidilinositol 3-Quinases/genética , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/patologia , Adulto , Carcinoma Papilar/enzimologia , Linhagem Celular Tumoral , Classe I de Fosfatidilinositol 3-Quinases , DNA de Neoplasias/genética , Feminino , Dosagem de Genes , Humanos , Hibridização in Situ Fluorescente , Masculino , Pessoa de Meia-Idade , Oriente Médio , Mutação Puntual , Reação em Cadeia da Polimerase , Proteínas Proto-Oncogênicas B-raf/genética , Análise de Sequência de DNA , Neoplasias da Glândula Tireoide/enzimologia , Proteínas ras/genéticaRESUMO
Formerly, fewer than 1% of patients with hypertension were believed to have primary hyperaldosteronism; however, recent studies have suggested a higher prevalence, in 5% to 10% of patients with hypertension. Hypokalemia is not necessary for the diagnosis and is probably a sign of more advanced disease. The best diagnostic test is the plasma aldosterone concentration to plasma renin activity (PAC/PRA) ratio. Excess aldosterone level has a deleterious effect on the cardiovascular system. Aldosteronomas should be differentiated from idiopathic hyperaldosteronism (IHA),because they are curable by laparoscopic adrenalectomy.
