Correlative study on neuro-endocrine differentiation and presence of somatostatin receptors in breast carcinomas.

To correlate the expression of neuro-endocrine (NE) markers with the presence of somatostatin receptors (SSR) in human breast cancer, a series of 100 cases was stained with the Grimelius silver procedure, by immunocytochemistry with specific NE markers (i.e., chromogranin A and B and synaptophysin) and by autoradiography for SSR. Nine cases were positive for at least one NE marker, while 4 cases were positive for all of them. SSR were detected in 17 cases, either with low (10 cases) or with high receptor density (7 cases). A highly significant correlation was established between the expression of NE markers and high SSR density. Our findings are additional evidence of the existence of a group of breast cancers showing morphological and cytochemical similarity with neuro-endocrine tumors present in other organs. The identification of this type of breast cancer is of biological and potential therapeutic interest.