Somatostatin receptor subtype mRNA expression in human colorectal cancer and normal colonic mucosae

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Published on Thursday, 26 February 2015

Abstract

Somatostatin analogues may be useful novel agents in the systemic treatment of advanced colorectal cancer, as somatostatin inhibits proliferation in a wide variety of cell types.

Here, we report the expression profiles of somatostatin receptor mRNAs in 32 pairs of malignant and normal colonic epithelia.

Receptor subtype 2 (hSSTR2) mRNA was detected throughout nearly 90% of both malignant and normal tissue by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization.

Subtype 5 (hSSTR5) mRNA was detected in 46% and 45% of tumour and mucosal samples respectively, but in 75% (9/12) of early-stage tumours (tubulovillous adenomas, Dukes' A and B) compared with 31% (5/16) of late-stage tumours (Dukes' C and 'D' tumours), 0.05>P>0.025 (chi2 with Yates' correction).

There was also reduced expression of hSSTR5 in samples of metastatic tumour (11%, 1/9) compared with all tumour samples (56%, 18/32) 0.025>P>0.01 (chi2 with Yates' correction).

Other hSSTRs (1, 3 and 4) were expressed infrequently.

Thus, hSSTR2 expression is retained after malignant transformation in colonic epithelium and, although it may potentially be a target for antiproliferative therapy, its ubiquitous expression militates against this.

hSSTR5 warrants investigation as a tumour suppressor.

 

 

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See also Somatostatin in oncology, the overlooked evidences.