Abstract
Purpose: :
Inhibitor of Apoptosis Proteins (IAP) have been implicated in the pathogenesis of variety of tumors including skin melanoma. We aim to characterize the expression of IAP genes in primary uveal melanoma tumors, liver metastasis from uveal melanoma, and uveal melanoma cell lines.
Methods: :
Samples were collected from six primary uveal melanomas, seven liver metastasis from uveal melanoma, four uveal melanoma cell lines, and normal retina, retinal pigmented epithelium (RPE), and choroid tissues. The expression of eight genes (XIAP, apollon, ML–IAP, Survivin, Naip, Birc2, Birc3, and Birc8) from the IAP family was assessed through RT–PCR. Microcirculation patterns were determined by immunostaining for laminin and by PAS staining on cryosections. Ki–67 immunostaining was preformed to exhibit cells undergoing proliferation, and cell type was assessed by conventional histology.
Results: :
Generally, IAP genes were expressed in melanoma and normal tissue samples (RPE, retina) excluding a minority of samples. An outstanding variability of XIAP and apollon gene expression was distinguished. These genes were expressed in a third and two thirds of the tumor samples, respectively. Neither of these genes was expressed in the normal tissues. By contrast, Survivin and ML–IAP were expressed in each of the tumor samples. Interestingly, none of the IAP family genes was expressed in normal choroid tissue.
Conclusions: :
Members of the IAP family show altered expression in primary and metastatic uveal melanoma. These proteins can inhibit tumor cell apoptosis and, thus, may potentially modulate uveal melanoma growth rate.
Keywords: melanoma • apoptosis/cell death • tumors