Frequent expression of immunoreactive somatostatin receptors in cervical and endometrial cancer
Abstract
OBJECTIVE: A variety of human cancers has been shown to express somatostatin receptors which can be utilized for in vivo tumor targeting. Although the somatostatin receptor status of mammary and ovarian cancer has been studied in detail, somatostatin receptors have not been examined in other gynecological malignancies such as cervical or endometrial carcinoma.
METHODS: We have previously developed a panel of somatostatin receptor subtype-specific antibodies that effectively stain formalin-fixed, paraffin-embedded human tumor tissue. In the present study, we have used these antibodies to determine the somatostatin receptor status of 21 randomly selected cervical carcinomas and 28 randomly selected endometrial carcinomas.
RESULTS: In cervical carcinoma, the incidence of somatostatin receptor expression was sst2A (12/21, approximately 57%) > sst3 (9/21, approximately 43%) > sst1 (8/21, approximately 38%) > sst4 (0/21, 0%) = sst5 (0/21, 0%). In endometrial carcinoma, the incidence of somatostatin receptor expression was sst3 (12/28, approximately 43%) > sst2A (11/28, approximately 39%) > sst1 (9/28, approximately 32%) > sst4 (1/28, approximately 4%) = sst5 (1/28, approximately 4%). Somatostatin receptor-like immunoreactivity was in most cases located at the plasma membrane and completely blocked with antigenic peptide. The expression of somatostatin receptor subtypes was independent of patient age, diagnosis, tumor stage, and histological grade.
CONCLUSION: Our findings reveal a previously unappreciated high incidence of sst1, sst2A, and sst3 somatostatin receptors in human cervical and endometrial cancers and suggest that a subgroup of receptor-positive uterine carcinomas may be a potential target for diagnostic and therapeutic intervention with stable somatostatin analogs.
See also Somatostatin in oncology, the overlooked evidences.