Expression of growth factors in brain tumors: correlation with tumor grade, recurrence and survival

Abstract

The aim of this study is to evaluate the correlation between the expression of some growth factors (GFs) and the tumor grade, recurrence and survival of brain glial and ependymal tumors. The expression of vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), tenascine, transforming growth factor (TGFbeta), isomeres, platelet-derived growth factor (PDGF) and p53 was studied in 40 primary brain tumors, both low-grade and high-grade, including astrocytomas, oligodendrogliomas, glioblastomas and ependymomas. The same GFs were also studied in 46 specimens of recurrent tumors from the same patients. The positivity and intensity of the immunohistochemical expression were correlated with the tumor grade, the interval and type of recurrence, and the survival. The expression of all GFs, excepting TGFbeta1, TGFbetaRI and tenascine, was found to be correlated with the tumor grade in all tumors of both astroglial and oligodendroglial origin, whereas ependymomas showed significant differences only for EGFR. Low-grade (Grade II) tumors recurring as anaplastic (Grade III) forms showed GF expression rather similar to initially high-grade gliomas and significantly higher than that of low-grade (Grade II) tumors in both initial surgery and recurrence. Besides, low-grade (Grade II) tumors recurring as low-grade showed significantly longer median recurrence time (5.4 vs. 3.5 years) and better median survival (8.3 vs. 5.4 years) than those recurring as anaplastic forms (WHO III). The immunohistochemical study of expression of VEGF, EGFR, TGFbeta2, TGFbeta3, PDGF and p53 in all low-grade (Grade II) brain gliomas at the first operation may help to differentiate cases with slower evolution and longer survival from those with higher potential of anaplastic transformation.