DO METALLOTHIONEINS AFFECT THE RESPONSE TO TREATMENT IN TESTIS CANCERS

Purpose: Data on the involvement of elevated metallothionein (MT) expr ession in resistance to some of the commonly used anticancer treatment s are scattered and conflicting. This encouraged us to examine further the contribution of metallothionein expression to the development of this resistance phenotype. Patients and methods: Formalin-fixed, paraf fin-embedded blocks of primary untreated germ cell testicular tumor sp ecimens, obtained from 77 patients following radical orchiectomy, were examined for their MT expression using monoclonal antibody and immuno histochemistry. Clinical staging, the chemotherapeutic schedule and ev aluation of response to treatment (defining objective response) were p erformed according to UICC criteria. Results: All tumor types, includi ng seminomas and nonseminomas, expressed MT, regardless of their histo logy and clinical stage. The immunoreactivity of MT showed a significa nt positive correlation with the clinical sensitivity of cancer to ant itumor therapy (P = 0.0001). Conclusion: In patients with germ cell te sticular tumors, high MT expression, as detected by immunohistochemist ry, predicts a better response rate to chemotherapy whereas tumors lac king or demonstrating low MT expression show a worse prognosis. These data do not support the hypothesis that MT overexpression contributes to cisplatinum resistance, at least in this tumor type.