Association of metallothionein expression and clinical response to cisplatin based chemotherapy in testicular germ cell tumors

INTRODUCTION: The protective roles of metallothioneins (MT) against metal toxicity suggest that MT may have a functional role in cisplatin resistance. The aim of this study was to investigate the expression of MT in specimens of germ cell tumors and compare it with clinical sensitivity to cisplatin based chemotherapy. MATERIAL AND METHODS: Tissue blocks of primary GCT specimens obtained from 39 patients were examined immunohistochemically for MT expression. Staining intensity was evaluated according to the percentage of MT positive cells and graded as [-], [+] and [++]. The staining characteristics were compared with the clinical response to chemotherapy. RESULTS: Of the 39 tumors, 3 evidenced no MT expression while 26 and 10 specimens showed [+] and [++] staining, respectively. Although seminomas tend to stain weaker than non-seminomas, the difference of staining between them was not significant (p = 0.19). Of the 39 patients, 23 underwent cisplatin based chemotherapy. Of those, 6 progressed and 17 achieved complete remission. Of the non-responders, 5 showed [+] and 1 showed [++] staining. Six of the responders showed [+], 10 had [++] and 1 showed no staining. No association was found between MT staining and chemo-sensitivity (p = 0.53). CONCLUSIONS: MT expression in primary germ cell tumors did not differ between responding and non-responding patients and therefore may not be useful in predicting response to chemotherapy.