Published in:
01-12-2015
Impact of gsp mutations in somatotroph pituitary adenomas on growth hormone response to somatostatin analogs: a meta-analysis
Authors:
Z. A. Efstathiadou, A. Bargiota, A. Chrisoulidou, G. Kanakis, L. Papanastasiou, A. Theodoropoulou, S. K. Tigas, D. A. Vassiliadi, M. Alevizaki, S. Tsagarakis
Published in:
Pituitary
|
Issue 6/2015
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Abstract
Objective
Somatic mutations in the GNAS1 gene, which encodes the alpha-subunit of G stimulatory proteins (gsp), are frequently detected in somatotroph pituitary tumors and have been associated to specific clinical and histopathological characteristics. However, the question whether the presence of a somatic gsp mutation affects the response to somatostatin analog treatment remains unresolved.
Design
Following a literature search, we performed a meta-analysis, including 8 eligible studies, in order to estimate the effect of gsp mutation on the percent reduction of growth hormone (GH) levels during an acute octreotide suppression test (OST). A total of 310 patients with acromegaly [126 gsp (+) and 184 gsp (−)] were included in the analysis.
Results
The presence of the gsp mutation was related with a greater reduction in GH levels on OST [Weighted Mean Difference (WMD): 9.08 % (95 % CI, 2.73, 15.42); p = 0.005; random effects model]. There was significant heterogeneity for this effect estimate (I2 = 58 %, p value for heterogeneity = 0.02). A sensitivity analysis after exclusion of a study with different methodology of OST provided similar estimates [WMD: 6.93 % (95 % CI, 1.40, 12.46); p = 0.01], albeit with no significant heterogeneity (I2 = 35 %, p value for heterogeneity = 0.16).
Conclusions
The present meta-analysis suggests a role for gsp mutation as a prognostic factor of treatment response to somatostatin analogs.