Bax, Bcl-2, fas and Fas-L antigen expression in human seminoma: correlation with the apoptotic index.
Apoptosis plays a crucial role in the regulation of spermatogenesis in male germ cells and is, at least in part, modulated by Bcl-2, Bax, and the Fas pathway. Seminomas have a favourable outcome and respond to radio-/chemotherapy with an increased rate of apoptosis. The expression of Bax, Bcl-2, Fas and Fas-ligand (Fas-L) in human seminoma was evaluated and correlated with the apoptotic index. Twenty-nine classical seminomas were examined by immunohistochemistry and Western blotting using antibodies against Bax, Bcl-2, Fas and Fas-L. Apoptosis was detected by in-situ end-labeling of fragmented DNA and the apoptotic index (AI) was determined. Expression of Fas was found in 26 (89.7%) of Fas-L in 24 seminomas (82.2%); none of the tumours expressed Bcl-2. No correlation between the AI and Fas, Fas-L or Bcl-2 expression was found. Bax was demonstrated in 20/29 tumours (69%). Bax-positive tumours showed an increased AI of 4.75 +/- 2.38% in contrast to 2.60 +/- 1.23% of the Bax-negative tumours (P = 0.002). The number of Bax-positive tumour cells and apoptotic cells revealed a significant correlation using chi2-test (P = 0.04) and linear regression (r = 0.54, P = 0.001). Therefore, Bax seems to play a determinant role in the modulation of apoptosis in human seminoma that may be linked to a favourable outcome.
Grobholz
Rainer
R
Department of Pathology, Ruprecht-Karls-University Heidelberg, University Hospital Mannheim, Germany. rainer.grobholz@path.ma.uni-heidelberg.de
Zentgraf
Hanswalter
H
Köhrmann
Kai-Uwe
KU
Bleyl
Uwe
U
D000328:Adult; D017209:Apoptosis; D053222:Fas Ligand Protein; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008875:Middle Aged; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D018239:Seminoma / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D013736:Testicular Neoplasms / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D051028:bcl-2-Associated X Protein; D019014:fas Receptor / Q000378:metabolism*
C494826:BAX protein, human; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D019014:fas Receptor