Abstract
Purpose: :
Uveal melanoma (UM) is the most common primary intraocular tumor in adults. In recent years, a number of candidate proteins have emerged as possible targets for managing metastatic UM. The purpose of this study was to investigate the expression of an established biomarker panel for therapeutic agents in primary and metastatic UM.
Methods: :
Five primary UM were obtained with matched liver, lung, bone, or orbital metastatic tissue. Immunohistochemistry was carried out on serial sections of the formalin-fixed, paraffin-embedded specimens with the following monoclonal antibodies: HMB-45, COX-2, IGF1R, Heat Shock Protein 90 (HSP90), C-met, C-Kit, and Kiss-1. A grading system of negative, mild, or intense staining was applied to evaluate all samples.
Results: :
Staining for HMB-45 was intense in the primary tumors and metastatic sites. All primary UM and corresponding metastatic lesions were positive for COX-2, C-Met, C-Kit and Kiss-1. COX-2 expression was mild in the bone and orbital metastases, and intense in the lung and liver metastases. Positive staining of IGF1R was intense in all specimens except for the orbital metastasis where it was not present. Kiss-1 expression was intense in all samples except for one matched primary and lung metastasis in which staining was mild. The expression of HSP90 was intense in four of five primary tumors as well as their metastatic sites. One patient was negative for HSP90 staining in both the primary and metastatic lesions.
Conclusions: :
The evaluation of a panel of biomarkers for uveal melanoma revealed that staining between primary and matched metastatic lesions are typically similar in expression and intensity. These results may prove beneficial in deciding on treatments for uveal melanoma; biomarker expression of primary tumors may be used to understand and treat covert metastases.
Keywords: melanoma • immunohistochemistry • tumors