ABSTRACT
<p><b>OBJECTIVE</b>To investigate the protein expression of human testis development related gene 1 (TDRG1) in human testicular cancer and its pathological significance.</p><p><b>METHODS</b>The expression levels of TDRG1 were detected in the testis tissues of testicular cancer patients and normal men by tissue microarray and immunohistochemistry, and the results were analyzed.</p><p><b>RESULTS</b>Immunohistochemistry exhibited positive expression of the TDRG1 protein in the testis of 73.3% (11/15) of the normal men, 83.3% (10/12) of the patients with embryonal carcinoma, 80.0% (8/10) of those with yolk sac tumor, 26.9% (7/26) of those with seminoma, and 57.1% (4/7) of those with teratoma. The expression levels of TDRG1 in the testis tissues of the seminoma and teratoma groups were shown to be significantly lower than that of the normal control (P < 0.01 and P < 0.05), but those of the embryonal carcinoma and yolk sac tumor groups exhibited no significant differences from that of the latter (P > 0.05).</p><p><b>CONCLUSION</b>The significantly reduced expression of the TDRG1 protein in patients with seminoma or teratoma indicates that TDRG1 may be a candidate cancer suppressor gene.</p>