H. Khalid et al., EXPRESSION OF THE SMALL HEAT-SHOCK PROTEIN (HSP) 27 IN HUMAN ASTROCYTOMAS CORRELATES WITH HISTOLOGIC GRADES AND TUMOR-GROWTH FRACTIONS, Cellular and molecular neurobiology, 15(2), 1995, pp. 257-268
1. Cellular expression and distribution of the stress response small h
eat shock protein 27 (hsp27) in 39 high-grade astrocytomas (27 gliobla
stoma multiformes, 12 anaplastic astrocytomas) and in 27 low-grade ast
rocytomas (grade I-II) were analyzed immunohistochemically. 2. The cor
relation between hsp27 expression and tumor growth fractions of the as
trocytomas was examined following Ki-67 immunostaining. 3. The hsp27 s
taining was cell cytoplasmic. The hsp27 immunopositive rate was signif
icantly higher in high-grade astrocytomas; the rates were 74% for glio
blastomas, 58% for anaplastic astrocytomas, and 37% for low-grade astr
ocytomas, The small and large tumor cells, especially in glioblastomas
, multinucleated tumor giant cells, tumor cells in the pseudopalisadin
g and necrotic areas, cells of the microvascular endothelial prolifera
tions, and tumor vascular smooth muscles were usually hsp27 positive,
The mean percentage of hsp27-positive cells was significantly higher i
n the glioblastomas alone and in the combined high-grade astrocytomas,
compared to the low-grade, and in recurrent rather than in primary hi
gh-grade astrocytomas. 4. The high-grade astrocytomas had a highly sta
tistical significant Ki-67 labeling index. The Ki-67 labeling indices
were significantly higher in the hsp27-positive than the hsp27-negativ
e astrocytomas, irrespective of the histological grade. In the high-gr
ade astrocytomas with a Ki-67 labeling index of five and above, 81% of
those tumors were hsp27 positive. 5. Thus, a large number of human as
trocytomas express hsp27, and hsp27 expression correlates with histolo
gical grades of astrocytoma and with tumor growth fractions. This bein
g the case, hsp27 is likely to have a role in the growth of human astr
ocytomas.