Acromegaly: correlation between expression of somatostatin receptor subtypes and response to octreotide-lar treatment.
About one-third of acromegalics are resistant to the clinically available somatostatin analogs (SA). The resistance is related to density reduction or different expression of somatostatin receptor subtypes (SSTR). This study analyzes SSTR's expression in somatotrophinomas, comparing to SA response, hormonal levels, and tumor volume. We analyzed 39 somatotrophinomas; 49% were treated with SA. The most expressed SSTR was SSTR5, SSTR3, SSTR2, SSTR1, and SSTR4, respectively. SSTR1 and SSTR2 had higher expression in patients that had normalized GH and IGF-I. SSTR3 was more expressed in patients with tumor reduction. There was a positive correlation between the percentage of tumor reduction and SSTR1, SSTR2 and SSTR3 expression. Also, a positive correlation between SSTR2 mRNA expression and the immunohistochemical reactivity of SSTR2 was found. Our study confirmed the association between the SA response to GH and IGF-I and the SSTR2. Additionally, this finding was also demonstrated in relation to SSTR1.
Casarini
Ana Paula M
AP
Neuroendocrine Unit, Division of Endocrinology and Metabolism, University of Sao Paulo Medical School, Av. 9 de Julho 3858 01406-100, Sao Paulo, SP, Brazil. anapaulabiomed@hotmail.com
Jallad
Raquel S
RS
Pinto
Emília M
EM
Soares
Iberê C
IC
Nonogaki
Suely
S
Giannella-Neto
Daniel
D
Musolino
Nina R
NR
Alves
Venâncio A F
VA
Bronstein
Marcello D
MD