Clinicopathological value of somatostatin type 2A and estrogen receptor immunoreactivity in human breast carcinoma.

Somatostatin type 2A (sstr2A) and estrogen receptor (ER) are interrelated regulatory receptors present in normal breast epithelium and in a population of breast carcinomas. ER mediates growth stimulatory effects of estrogens whereas sstr2A mediates growth inhibitory actions of somatostatin. However, much work has been devoted to elucidate the biological role of ER, little is known about sstr2A in breast cancer. In the present study we examined immunoreactivity of sstr2A and ER in 64 breast carcinomas in correlation with tumor size and histological grade (HG), presence of lymph node metastasis (LNM), Nottingham prognostic index (NPI), and the patients' age. ER and sstr2A immunoreactivity were present in 78% and 63% of the breast carcinomas, respectively. Ninety percent of tumors immunoreactive for sstr2A were simultaneously immunoreactive for ER. ER immunoreactivity correlated significantly with lower HG (p = 0.03) and better NPI (p = 0.02). sstr2A immunoreactivity correlated significantly with lower HG (p = 0.012) but not with NPI (p = 0.26). There was no correlation of sstr2A immunoreactivity and tumor size, patients' chronological age or LNM. The results confirm prognostic value of ER immunohistochemistry in breast carcinoma. However sstr2A cannot substitute ER for prognostic evaluation, sstr2A immunoreactivity being significantly associated with lower HG seems to represent an independent prognostic factor in breast carcinoma.