2048

EPHB2

CAPB|DRT|EK5|EPHT3|ERK|Hek5|PCBC|Tyro5;EPH receptor B2;EPHB2;EPH receptor B2

EPH-like kinase 5|developmentally-regulated Eph-related tyrosine kinase|elk-related tyrosine kinase|eph tyrosine kinase 3|ephrin type-B receptor 2|protein-tyrosine kinase HEK5|renal carcinoma antigen NY-REN-47|tyrosine-protein kinase TYRO5|tyrosine-protei

1p36.1-p35

protein-coding

Malignant gliomas are the most common and the deadliest brain malignancies in adults. Despite the lack of a complete understanding of the biology of these tumors, significant advances have been made in the past decades. One of the key discoveries made in the area of malignant gliomas is that these tumors can be induced and maintained by aberrant signaling networks. In this context, the Ras pathway has been extensively exploited, from both basic and translational perspectives. Although somatic oncogenic mutations of Ras genes are frequent in several cancer types, early investigations on gliomas revealed disappointing facts that the Ras mutations are nearly absent in malignant gliomas and that theBRAF mutations are present in a very small percentage of gliomas. Therefore, theobserved deregulation of the Ras-RAF-ERK signaling pathway in gliomas is attributed to its upstream positive regulators, including, EGFR and PDGFR known to be highly active in the majority of malignant gliomas. In contrast to the initial negative results on the somatic mutations of H-Ras, K-Ras and BRAF, recent breakthrough studies on pediatric low-grade astrocytomas uncovered genetic alterations of the BRAF gene involving copy number gains and rearrangements. The7q34 rearrangements result in a novel in-frame KIAA1549:BRAF fusion gene that possesses constitutive BRAF kinase activity resembling oncogenic BRAF (V600E). In light of the earlier findings and recent breakthroughs, this review summarizes our current understanding of the Ras-RAF-ERK signaling pathway in gliomas and the outcome of preclinical and clinical studies that evaluated the efficacy of Ras-targeted therapy in malignant gliomas.

BACKGROUND: Wilms tumor is the most common pediatric renal malignancy, but the parameters that are important to its invasion capacity are poorly understood. The aim of this study was to identify new proteins associated with the invasion capacity of Wilms tumor. PROCEDURE: Gene expression profiles for 15 primary Wilms tumor samples were determined by Affymetrix Genechip(R) Human Genome Ul33A microarray analysis. The gene expression profiles for selected genes was furtherconfirmed by quantitative RT-PCR analysis. Immunohistochemical analysis was performed on 25 Wilms tumor cases to confirm expression for Bcl2A1, EphB2, MSX1,and RIN1. RESULTS: Using microarray analysis 14 genes showed differential expression (P < 0.05) comparing stage 1 non-invasive Wilms tumor to stages 2-4 invasive Wilms tumor. The differential expression for Bcl2A1, EphB2, MSX1, and RIN1 was confirmed by quantitative RT-PCR. MSX1 protein was statistically significantly lower in stages 2-4 invasive Wilms tumor cases compared to stage 1non-invasive cases (P = 0.013). EphB2 protein was higher in stages 2-4 Wilms tumor cases compared to stage 1 cases (P = 0.006). There was no statistically significant difference between stages 1 and 2-4 Wilms tumor for Bcl2A1 (P = 0.230) or RIN1 (P = 0.969) at the protein level. CONCLUSION: Our results indicate that MSX1 may be associated with the invasion capacity of Wilms tumors. RIN1 is a downstream effector of RAS and Bcl2A1 functions as an anti-apoptotic protein. EphB2 is an ephrin receptor and is up-regulated in invasive tumors but its role needs to be confirmed in further cases of Wilms tumors.#CI- Copyright (c) 2011 Wiley-Liss, Inc.