Background & aims: Neuropeptide receptors, expressed at high density by neoplastic cells, can be instrumental for diagnosis and therapy. However, little is known about neuropeptides and neuropeptide receptors in the tumor bed. The aim of this study was to study the expression of two neuropeptide receptors in peritumoral blood vessels.
Methods: Somatostatin and substance P receptors were measured using in vitro receptor autoradiography in well-defined submucosal and subserosal vessels located in the immediate surroundings of human colorectal carcinomas or in normal colon taken at increasing distances from the tumor.
Results: Both receptors were 3-5-fold overexpressed in the host veins within a 2-cm-wide area surrounding human primary colorectal carcinomas compared with veins located at 5-10-cm distance in normal gut tissue. The expression of peritumoral vascular somatostatin receptor and substance P receptor appears independent of receptor expression in the tumor, of tumor stage, and of the grade of local inflammation.
Conclusions: These biochemical alterations of veins in the immediate vicinity of tumors represent a novel tumor-related site of expression for the two receptors and may point to a new biological principle of host-tumor interaction. Thus, vascular regulatory mechanisms in the tumor bed may be important for tumor development and metastasis and may be used as a target for tumor therapy.