Oligodendrogliomas in relation to astrocytes differentiation. Clinicopathologic and immunohistochemical study.

Oligodendroglioma usually arise in adults and rarely in children. The objective of the current study was to evaluate the immunoexpression of glial fibrillary acidic protein (GFAP) and heat shock proteins (HSP70), endothelial vascular growth factor (EVGF), and endothilial vascular growth factor receptor type II (EFGF-R) expression in relation to the proliferation labeling index (proliferating cell nuclear antigen [PCNA]) and vascular density in patients with oligodendroglioma. We studied 28 cases of oligodendrogliomas--20 (71.4%) were oliodendrogliomas (grade II), and 8 (28.6%) cases were anaplastic oligodendroglioma (grade II according to World Health Organization classification). Eleven cases were male (39.28%) and 9 (32.14%) cases were female. Mitosis were found in grade II (0.35 +/- 1.14) and grade III (3.88 +/- 1.81) (P = .0001*) and pleomorphism in grade II (4.40 +/- 0.99) and grade III (9.50 +/- 9.20) (P = .028). The GFAP was positive in grade II (1.45 +/- 0.60) and grade III (2.63 +/- 0.52) (P = .000); HSP70 was immunoreactive in grade II (1.35 +/- 0.59) and grade III (2.50 +/- 0.53) (P = .001); and EVGF was immunoreactive in grade II (22.70 +/- 6.10) and grade III (36 +/- 1.63) (P = .043). The EVGF-RII was immunoreactive in grade II, 18.30 +/- 6.11 and 31.63 +/- 4.93 (P = .045). The microvascular density labeling index rates were 20.70 +/- 4.34 (grade II) and 33.38 +/- 5.29 (P = .000), and the PCNA labeling index rates were 32.95 +/- 5.89 (grade II) and 56.88 +/- 5.62 (grade III) (P = .045). We observed astrocyte differentiation in oligodendrogliomas grade III. We found a higher PGAF, HSP70, EVGF, and EFGF-R expression in relation with the PCNA and vascular density (CD34) in patients with oligodendroglioma grade III than in oligodendroglioma grade II. There was a significant relationship between mitosis, glial fibrillary acidic protein (GFAP), HSP70, EVGF, EVGF-receptor II expression, and the histologic grade and size of the tumor. For that reason, we suggest that the correlation between GFAP and HSP70 could have a relationship with the protection mechanism of the tumor itself.