Evaluation of the expression of somatostatin receptors by immunohistochemistry in neuroendocrine tumors of the small intestine.

Most neuroendocrine neoplasms (NEN) are characterized by the presence of somatostatin receptors (SSTR) which we use in location diagnostics and treatment. The aim of this study was to evaluate the expression of somatostatin receptors by immunohistochemistry in tissue obtained after surgery of the primary focus in the small intestine. The group of patients consisted of 41 people, in 18 cases the primary tumor was in the jejunum and in 23 in the ileum. The immunohistochemical method was used to visualize the receptors, using polyclonal antibodies in a two-stage peroxidase method. In patients with NEN of the small intestine, the SSTR2a and SSTR5 receptors are most commonly expressed, followed by SSTR2b and 3. In statistical analysis, it was shown that the expression of somatostatin receptors was not dependent on the primary site of the tumor (p > 0.05). The dependence of SSTR expression on histological maturity is evident. SSTR1, SSTR2b, SSTR3 and SSTR5 are more common in tumors with grading G1 (p < 0.05). In the study group, the exception was SSTR2a, whose incidence was comparable in both groups (p = 0.35). In NEN of the small intestine, the expression SSTR2a and SSTR5 is the most common.