THE ROLE OF THE INTEGRIN FAMILY OF ADHESION MOLECULES IN THE DEVELOPMENT OF TUMORS METASTATIC TO THE ORBIT

Tumors metastatic to the orbit frequently originate from certain prima ry tumors such as breast, lung, prostate, and melanoma. The site-speci fic nature of orbital metastases, as well as that of other metastatic lesions, cannot be the result of random seeding. We present evidence f rom a review of the literature demonstrating that tumor cells express adhesion molecules of the integrin family, and that these receptors pl ay a pivotal role in the development of a metastatic colony. We invest igated orbital metastatic lesions from prostate carcinoma, malignant m elanoma, and lobular breast carcinoma to determine the level of integr in expression by immunohistochemistry. Several integrin subunits (alph a(2), alpha(4), beta(3)) were found to have increased expression in th e metastasis when compared to normal prostate tissue and normal melano cytes. The increased expression of these integrins may be responsible for the tendency of these tumors to metastasize to the orbit, as well as for the tendency of prostate tumors to metastasize to bone. The res ults from the staining of the breast metastasis were inconclusive.