Osteopontin (OPN) is a phosphorylated glycoprotein with diverse functions including angiogenesis, cancer development, invasion and metastasis. The aim of the study was to analyze the expression of OPN in human astrocytomas and to correlate it with angiogenesis and patients' outcome. Seventy-six human astrocytomas including eight pilocytic astrocytomas (grade I), 10 diffuse astrocytomas (grade II), 8 anaplastic astrocytomas (grade III) and 50 glioblastomas (grade IV) were immunohistochemically stained for OPN protein. The distribution of OPN staining (cytoplasmic and/or interstitial) was assessed and compared to microvessel number and patients' survival. In normal brain tissue some glial and neuronal cells showed weak cytoplasmic staining, while interstitium was negative. Astrocytomas were heterogeneous regarding the OPN expression. High cytoplasmic OPN expression in glioblastomas was associated with poor patients' survival (p = 0.012). Also, we found the association of interstitial OPN expression and angiogenesis (p = 0.033), i.e. the number of newly formed blood vessels was higher in tumors showing high interstitial OPN expression. Our results indicate the overexpression of OPN protein in astrocytoma cells and suggest the role of OPN in astrocytoma progression and angiogenesis.

Background: The role of angiogenesis in the pathogenesis of renal cell carcinoma is well recognized, however, the influence of tumor cells in this activity has not yet been fully clarified. The aim of this study was to analyze the expression of hypoxia inducible factor-1α (HIF-1α), a regulatory factor of angiogenic switch, in comparison to vascular endothelial growth factor A and C (VEGF-A and VEGF-C), recognized to be involved in blood and lymph vessel neoangiogenesis, with potential association in the prognosis of patients with renal cell carcinoma.

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BackgroundThe role of epidermal growth factor (EGF) and its receptor (EGFR) in the pathogenesis and progression of various malignant tumors has long been known, but there is still disagreement concerning prognostic significance of EGFR expression in clear cell renal cell carcinoma (CCRCC). The present study was designed to analyze more objectively the protein EGFR expression in CCRCC and to compare its value with EGFR gene copy number changes and clinicopathologic characteristics including patient survival.MethodsThe protein EGFR expression was analyzed immunohistochemically on 94 CCRCC, and gene copy number alterations of EGFR by FISH analysis on 41 CCRCC selected according to distinct membrane EGFR staining.ResultsMembrane EGFR expression in tumor cells was heterogeneous with respect to the proportion of positive cells and staining intensity. FISH analysis did not reveal EGFR gene amplification, while polysomy of chromosome 7 found in 41% was associated with higher EGFR membrane expression. Moreover, EGFR overexpression was associated with a higher nuclear grade, larger tumor size and shorter patient's survival, while there was no connection with pathological stage.ConclusionIn conclusion, the protein expression of EGFR had an impact on prognosis in patients with CCRCC, while an increased copy number of chromosome 7 could be the possible reason for EGFR protein overexpression in the absence of gene amplification.

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