Stress-response (heat-shock) protein 90 expression in tumors of the central nervous system: an immunohistochemical study

This retrospective study deals with the expression of stress-response (heat-shock) protein 90 (srp 90) in a series of 148 human brain tumors. Immunohistochemical procedures were employed; cells of the human breast cancer line MCF 7 exposed to hyperosmolar stress served as positive controls. Deposits of reaction products were found in the cytoplasm and they displayed a granular pattern. srp 90 was detected in 14/31 meningiomas and 5/10 breast cancer metastases to the brain. The protein was also present in 6/13 glioblastomas and 7/18 astrocytomas. In addition, a positive reaction was found in 2/10 medulloblastomas, 2/14 primitive neuroectodermal tumors, 1/11 pituitary tumor, 2/21 schwannomas and 2/11 lung tumor metastases; however, oligodendrogliomas and primary malignant lymphomas were not stained. The srp 90 was detected in Western blots of meiningioma tissue homogenates. No significant immunohistochemical reaction was seen with sections of normal human cerebra, brain stem, cerebella, pituitary glands and spinal cords. These results document the expression of srp 90 by a variety of primary and metastatic intracranial tumors.