engleski

The expression of osteopontin in renal-cell carcinomas

BACKGROUND: Osteopontin (OPN) is phosphoprotein secreted by many cell types including osteoclasts, macrophages, activated T cells, smooth muscle cells and some epithelial cells. OPN binds to a variety of cell surface receptors including integrins and CD44 variant isoforms. It has been implicated in bone remodeling, wound healing, cellular immunity and angiogenesis. It is overexpressed in various experimental models of malignancy and appears to be involved in tumorigenesis and tumor cell metastasis. AIMS: The aim of this study was to analyze the expression of OPN in renal-cell carcinomas (RCC) and to evaluate its prognostic value. MATERIALS AND METHODS: The expression of OPN was immunohistochemically evaluated on 123 RCC: 110 were of conventional type (CRCC), 12 papillary and 1 collecting duct carcinoma. The expression on CRCC was compared to usual clinicopathological parameters such as nuclear grade and pathological stage. The statistical analysis was performed by x2 test. RESULTS: The OPN protein was upregulated in 50 CRCC (45, 5%) and was expressed as cytoplasmic granular positivity of various intensities. The statistical analysis showed the correlation of the OPN expression with Fuhrman nuclear grade (p<0, 0005) and pathological stage (p<0, 01). All papillary RCC showed strong and diffuse cytoplasmic positivity, irrespective of the nuclear grade. Also, the papillary component of CRCC was always strongly positive and accentuated compared to other, nonpapillary parts of the tumor. The collecting duct carcinoma also showed strong and diffuse expression of OPN protein. CONCLUSION: The OPN protein is overexpressed in renal-cell carcinomas and its expression strongly correlates with tumor progression and with the papillary architecture.

immunohistochemistry; osteopontin; prognosis; renal cell carcinoma

nije evidentirano