P53, bcl-2 and bax immunoreactivity as predictors of response and outcome after chemotherapy for metastatic germ cell testicular tumours

Objective To evaluate the roles of p53, bcl-2 and bax as determinants of chemosensitivity in testicular cancers and to assess whether immunohistochemical expression of these proteins in testicular germ cell tumours (GCTs) could be used to predict the outcome in patients with metastatic testicular GCTs. Patients and methods Immunoreactivity For p53, bcl-2 and bax were examined in primary testicular tumours from 24 patients with metastatic GCTs who were treated with bleomycin, etoposide and cisplatin chemotherapy. All immunostaining results were scored for the appropriate percentage of positive tumour cells and relative immunostaining intensity (score range 0-15) and compared with the response of the patients to chemotherapy. Results Overall, 20 (83%), 13 (54%) and 24 of the 24 GCTs showed greater than or equal to 1% immunoreactivity with p53, bcl-2 and bax, respectively. Only the bax immunostaining intensity and score had statistically higher mean values in the nonseminoma than in seminoma GCTs (P=0.047 and P=0.027, respectively). Only p53 immunostaining intensity, percentage of p53 immunopositive cells and p53 staining score were significantly different among the response groups. The median survival after chemotherapy was 30.5 months: however, taking the median values of the immunostaining scores as threshold values For the survival analysis, none of the three proteins were associated with significant differences in survival. Conclusions The incidence of p53 and bax immunoreactivity in testicular GCTs is higher than that of bcl-2 immunoreactivity. However, only p53 immunoreactivity could be used to predict the response to chemotherapy. P53, bcl-2. and bax scores were not significant prognostic factors for survival after che motherapy.