Replication protein A: a reliable biologic marker of prognostic and therapeutic value in human astrocytic tumors.

Replication protein A is a single-stranded DNA-binding protein that is required for the stabilization of single-stranded DNA and identified in replication foci where members of cyclin-dependent kinases-cyclin complexes are also present. In this study, we investigated the expression of replication protein A1 and replication protein A2 subunits of replication protein A protein in correlation with cyclins D2 and D3 and nuclear factor κB expression and assessed their prognostic significance in 66 patients with astrocytomas. Statistically significant positive associations emerged between (a) replication protein A1 and replication protein A2 protein expression (P < .0001); (b) cyclins D2 and D3 expression (P < .0001); (c) replication protein A1, replication protein A2, and cyclins D2 and D3 expression and histologic grade (P = .0001 in all correlations); (d) replication protein A1 and cyclin D2 or D3 expression (P < .0001 in both relationships); and (e) replication protein A2 and cyclin D2 or D3 expression (P < .0001 in both relationships). Nuclear factor κB1/p50 expression was positively correlated with replication protein A1, replication protein A2, and cyclins D2 and D3 expression, although these relationships failed to retain statistical significance when they were adjusted for histologic grade. Replication protein A2 expression seemed to independently affect survival in grade IV (P = .005) as well as in the entire cohort (P = .006). None of the molecules under study seemed to influence survival in lower grades (II/III), either by univariate or by multivariate analysis. In conclusion, replication protein A1, replication protein A2, and cyclins D2 and D3 seem to have a parallel role in the promotion of cell cycle in astrocytic tumors being implicated in the malignant progression of these neoplasms. Moreover, replication protein A2 protein seems to be a useful prognostic indicator in patients with astrocytomas.

Expression of nuclear factor-kappaB in human astrocytomas: relation to pI kappa Ba, vascular endothelial growth factor, Cox-2, microvascular characteristics, and survival.

Although NF-kappaB has been reported to be constitutively activated in various neoplasms, little information is available about its clinical significance in astrocytomas. In this study, we investigated the association of NF kappa B1/p50 and pI kappa Ba immunohistochemical expression with clinicopathologic features, vascular endothelial growth factor, Cox-2, and microvascular parameters in paraffin-embedded tissue from 82 patients with astrocytomas. pI kappa Ba expression was positively correlated with nuclear (P = .0010) and negatively with cytoplasmic (P = .0008) NF kappa B1/p50 expression. Nuclear NF kappa B1/p50 and pI kappa Ba expression increased with tumor grade (P = .0001 and P < .0001). Nuclear NF kappa B1/p50 was associated with vascular endothelial growth factor (P = .0079), Cox-2 (P = .0500), and total vascular surface area (P = .0430), although the latter was significant only in grades II and III. pI kappa Ba was also positively correlated with microvessel caliber (pI kappa Ba/area; P = .0087). Multivariate analysis selected NF kappa B/p50 expression as an independent prognosticator not only for the entire cohort (P = .0220), but also for grades II and III (P = .0029) and grade IV cases (P = .0310). Our results suggest that nuclear NF kappa B1/p50 expression is dictated by its interaction with I kappa Ba in astrocytomas and is associated with tumor grade and angiogenic factors, denoting the importance of nuclear NF kappa B/p50 expression in patients' prognosis.