DIFFERENTIAL EXPRESSION OF GLUTATHIONE S-TRANSFERASES IN GERM-CELL TUMORS OF HUMAN TESTES

Glutathione S-transferase (GST) isoenzymes alfa, mu and pi were assess ed by Western blotting in normal testes, seminomas and non-seminomatou s germ cell turners (NSGCTs). GST alfa and mu were strongly expressed in all normal specimens (n = 6), the pi isoform, however, could not or barely be detected. Ten (92%) of 11 seminomas had GST pi and only 2 ( 16%) showed alfa expression. In contrast twelve (80%) of 15 NSGCTs sho wed a significant level of GST alfa and only 2 (13%) had GST pi expres sion. The absence or paucity of mu isoform was characteristic for all neoplastic testicular tissues. A statistically significant relationshi p (P = 0.021) could be established between GST alfa and stages of dise ase, i.e., alfa isoform was prevalent in the later stage (IIB, III) NS GCT tumors. These results suggest that the poor prognosis of the later stage NSGCTs may be due to their high GST alfa content, while the GST pi does not seem to have role in this relation.