Differential expression of somatostatin receptor subtypes in hepatocellular carcinomas
Michael Bläker1, Michael Schmitz, Andreas Gocht
1Medizinische Klinik I, Zentrum für Innere Medizin, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. blaeker@uke.uni-hamburg.de
Background/Aims:
Somatostatin analogues inhibit cell proliferation by stimulation of distinct somatostatin receptor (SSTR) subtypes. In recent years, these compounds have been introduced into the therapy of advanced hepatocellular carcinoma (HCC). The efficacy of this treatment is under debate due to the controversial results of clinical trials. Despite the widespread clinical use of somatostatin analogues in HCC, little is known about the expression of each of the five SSTRs in these tumors.
Methods:
We analyzed the expression of SSTR subtypes in 56 HCCs by immunohistochemistry using subtype-specific antibodies. Six of the samples were also investigated by RT-PCR using subtype-specific oligonucleotide primers.
Results:
HCCs display differential, individual expression patterns as well as variable expression levels for SSTRs. The overall expression rate of SSTR1, SSTR2, SSTR3, SSTR4, and SSTR5 is 46, 41, 64, 0, and 75%, respectively. No significant correlation was observed between SSTR expression and tumor stage, differentiation, histological tumor type, or underlying liver disease.
Conclusions:
Individual patterns and levels of SSTR expression might determine the response to treatment with somatostatin analogues in HCC. Selective treatment of these tumors based on the analysis of SSTR subtype expression might lead to an increase in response rates.
Insights
Somatostatin receptor (SSTR) expression varies in hepatocellular carcinoma (HCC). Analyzing SSTR subtypes may improve treatment response to somatostatin analogues in HCC patients.
Area of Science:
- Oncology
- Molecular Biology
- Gastroenterology
Background:
- Somatostatin analogues (SA) are used to treat advanced hepatocellular carcinoma (HCC).
- Their efficacy in HCC is debated due to conflicting clinical trial results.
- Understanding somatostatin receptor (SSTR) expression in HCC is crucial for optimizing SA therapy.
Purpose of the Study:
- To investigate the expression patterns of all five SSTR subtypes (SSTR1-5) in HCC.
- To correlate SSTR expression with clinicopathological features of HCC.
Main Methods:
- Immunohistochemistry was used to analyze SSTR subtype expression in 56 HCC samples.
- RT-PCR was performed on six samples for further validation of SSTR expression.
Main Results:
- HCCs exhibit diverse and individual SSTR expression profiles.
- Overall expression rates for SSTR1, SSTR2, SSTR3, SSTR4, and SSTR5 were 46%, 41%, 64%, 0%, and 75%, respectively.
- No significant correlation was found between SSTR expression and tumor stage, differentiation, histology, or liver disease.
Conclusions:
- Individual SSTR expression patterns in HCC may influence treatment response to SA.
- Tailoring SA treatment based on SSTR subtype analysis could potentially enhance patient response rates.
