Quantitative Analysis of Somatostatin and Dopamine Receptors Gene Expression Levels in Non-functioning Pituitary Tumors and Association with Clinical and Molecular Aggressiveness Features.

Álvaro Flores-Martinez,Eugenio Cárdenas-Valdepeñas,Eva Venegas-Moreno,Ainara Madrazo-Atutxa,Justo P Castaño,Ariel Kaen,Alfonso Soto-Moreno,Florinda Roldán,Pablo Remón-Ruiz,Elena Dios,M Carmen Vázquez-Borrego,Noelia Gros-Herguido,Miguel A Japón,Raúl M Luque,David A Cano

doi:10.3390/jcm9093052

Abstract

The primary treatment for non-functioning pituitary tumors (NFPTs) is surgery, but it is often unsuccessful. Previous studies have reported that NFPTs express receptors for somatostatin (SST1-5) and dopamine (DRDs) providing a rationale for the use of dopamine agonists and somatostatin analogues. Here, we systematically assessed SST1-5 and DRDs expression by real-time quantitative PCR (RT-qPCR) in a large group of patients with NFPTs (n = 113) and analyzed their potential association with clinical and molecular aggressiveness features. SST1-5 expression was also evaluated by immunohistochemistry. SST3 was the predominant SST subtype detected, followed by SST2, SST5, and SST1. DRD2 was the dominant DRD subtype, followed by DRD4, DRD5, and DRD1. A substantial proportion of NFPTs displayed marked expression of SST2 and SST5. No major association between SSTs and DRDs expression and clinical and molecular aggressiveness features was observed in NFPTs.

Highlights

Non-functioning pituitary tumors (NFPTs) are characterized by the absence of clinical symptoms related to pituitary hormone overproduction
Our cohort of patients with NFPTs was composed of different histological subtypes, in similar proportions to what has been observed in previous large series of this type of tumors [27]
Most of NFPTs were gonadotropin-storing tumors, followed different histological subtypes, in similar proportions to what has been observed in previous large series of this type of tumors [27]

Summary

Introduction

Non-functioning pituitary tumors (NFPTs) are characterized by the absence of clinical symptoms related to pituitary hormone overproduction. In the limited number of studies published to date, SSTs expression has been analyzed at the mRNA level [11,12,13] or by immunohistochemistry (IHC) [14,15] but rarely both methods have been applied simultaneously in the same study. This is an important point, as a consistent method for evaluating SST1-5 expression in pituitary tumors has yet to be implemented in a clinical pathology setting

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