The immunohistochemical expression of stress-response protein (srp) 60 in human brain tumours: Relationship of srp 60 to the other five srps, proliferating cell nuclear antigen and p53 protein

This study analyzed the expression of stress-response (heat-shock) protein 60 (srp 60) in a series of 158 human brain tumours. Immunohistochemical pro cedures were employed; cells of the human cervical cancer line HeLa S3 expo sed to hyperosmolar stress served as positive controls. Deposits of reactio n products were found in the cytoplasm. Approximately half of the glioblast omas multiforme (17/31), breast carcinoma metastases (6/10), and lung carci noma metastases (5/11) as well as about one-third of the astrocytomas (5/13 ) and meningiomas (8/23) had tumour cells that expressed srp 60. A positive reaction for srp 60 was also seen in some medulloblastomas (2/16), primiti ve neuroectodermal tumours (PNETs) (2/11), schwannomas (2/21), and pituitar y adenomas (2/7), but no positive reactions were observed with oligodendrog liomas and ependymomas. Compared with srp 60-negative tumours, srp 60-posit ive turnours coexpressed one or more stress-related proteins, among which s rp 90, srp 72, srp 27, alphaB-crystallin and ubiquitin occurred with higher frequencies; a high correlation between srp 60 and the other five srps (0. 88 - 0.97, p<0.01, Pearson correlation coefficient) was observed in srp 60- positive tumours. In contrast, the correlation coefficient in srp 60-negati ve tumours was not significant (-0.26 - 0.71). There was a tendency for the proliferating cell nuclear antigen (PCNA)-labeling index to be higher in g lioblastomas, astrocytomas, medulloblastomas, PNETs, and breast and lung ca rcinoma metastases that expressed srp 60 than in those that did not. No sig nificant immuno histo chemical reactions of srp 60, PCNA and p53 protein we re seen with sections of normal brain tissues. We conclude that primary and metastatic turnours of the brain produce srp 60 and that srp 60 in certain brain tumour cells may coexpress the other five srps. In addition, srp 60 expression might depend, in part, on proliferating potential.