Expression of cathepsin D in human astrocytic neoplasias.

The authors investigate the expression of enzyme cathepsin D in human astrocytic neoplasias revealing the dependency on the grade of anaplasia of the tumor. This investigation has shown that there is a significant difference of cathepsin D-expression between the group of low malignant astrocytomas (G1 and G2) and the group of highly malignant astrocytomas (G3 and glioblastoma). Enzyme expression decreases when the grade of anaplasia increases. Parallel experiments have shown that in the investigated tumors the expression of GFAP also decreases when the grade of anaplasia increases. These results are related to the role of cathepsin D in the protein metabolism of healthy human CNS. The authors assume that in low malignant tumors, owing to the persisting and well-developed cytoskeleton, the investigated enzyme cathepsin D expresses more strongly than in highly malignant tumors, which are characterized by a heavier loss of their capability to express regular structures so that cathepsin D finds less substrate and, correspondingly, expresses less strongly.