Brain tumor: immunohistochemical studies on the stress-response proteins, p53 protein and proliferating cell nuclear antigen.

Abstract

This retrospective immunohistochemical study compares the expression of five stress-response (heat-shock) proteins (srp's) [srp 90, srp 72, srp 27, alpha B-crystallin and ubiquitin], p53 protein and proliferating cell nuclear antigen (PCNA) in 118 primary brain tumors and 21 carcinoma metastases to the central nervous system. Serial sections of formalin-fixed, paraffin-embedded tissues were used. Most astrocytomas (9/13), ependymomas (5/5), glioblastoma multiforme (GBM) (11/12), schwannomas (19/21), meningiomas (22/23) and breast carcinoma metastases (Br-Mt) (9/10), and some medulloblastomas (5/15), primitive neuroectodermal tumors (PNETs) (5/11), pituitary adenomas (4/7) and lung carcinoma metastases (6/11), but none of 10 oligodendrogliomas had tumor cells that expressed one or more (up to five) srp's. The percentage of tumors with p53-positive cells was variable; the proportion was highest among srp-expressing GBMs (mean: 16.1%) and Br-Mts (mean: 15.3%). The mean PCNA-labeling index (LI) also varied, ranging from 1.2% in the group of pituitary adenomas to 24.5% in Br-Mts, with GBMs (20.4%) and medulloblastomas (18.4%) approaching the latter value. PCNA-LI was higher in the astrocytomas, GBMs, medulloblastomas and PNETs that expressed srp's than in those did not. A high proportion of p53-positive cells (31.3 to 59.0%) and the highest PCNA-LIs (41.0 to 49.0%) were seen in two GBMs and one Br-Mt that expressed all five srp's. We conclude that primary and metastatic tumors of the brain produce one or more stress-related proteins, and that a variable proportion of the tumor cells have immunohistochemically-detectable p53, the expression of which may depend, at least in part, on the growth potential of a given tumor.