Somatostatin receptor expression in adrenocortical carcinomas

Abstract

Background. Adrenocortical carcinoma (ACC) is a rare malignant tumor characterized by an annual incidence of 0.5—2 cases per million population. Surgery is the-first line treatment for ACC. When total tumor resection is not possible due to its proliferation or progression, mitotane (o,p’DDD) is used. In this case, stabilization and partial response (as assessed by RECIST criteria) was observed only in 48.7% of cases, necessitating the search for new therapeutic targets.
 Objective — the study was aimed at assessing the somatostatin receptor expression in adrenocortical carcinomas and adrenal cortex tumors with uncertain malignant potential.
 Material and methods. Surgical material from adrenocortical tumors of 13 patients (4 males and 9 females aged from 28 to 68 years) was used. In all cases, the diagnosis was verified by morphological and immunohistochemical (IHC) studies: ACC was detected in 10 cases (including 1 case of ACC liver metastasis), oncocytic carcinoma — 1 case, oncocytoma with uncertain malignant potential — 2 cases. Morphological assessment of ACC was carried out according to Weiss criteria (for ACC tumors) and Lin—Weiss—Bisceglia criteria (for oncocytic neoplasms of the adrenal cortex). IHC study was carried out with antibodies to the spectrum of adrenal cortex-specific markers, as well as Ki-67 and somatostatin receptors 2 and 5 (SSTR2 and SSTR5).
 Results. The expression of SSTR2 and/or 5 was detected in 8 (61.5%) of 13 cases of ACC. Isolated SSTR2 expression was observed in 4 cases (4/13), while SSTR5 expression was observed in 6 cases (6/10). In 2 cases (2/10), co-expression of both receptor types was observed. SSTR expression was observed both in ACC and ACC liver metastasis, as well as in oncocytic ACC.
 Conclusion. SSTR2 and/or 5 expression in ACC tissue expands diagnostic and prognostic capabilities for this pathology.