PROLIFERATING CELL NUCLEAR ANTIGEN EXPRESSION TO PREDICT OCCULT DISEASE IN CLINICAL STAGE-I NONSEMINOMATOUS TESTICULAR GERM-CELL TUMORS

We analyzed primary tumor tissue from 89 clinical stage I nonseminomat ous germ cell testicular tumor patients for proliferating cell nuclear antigen expression and histological features to determine if these el ements could distinguish pathological stage I (52 patients) from patho logical stage II disease or patients who later had relapse (37). Using a monoclonal antibody (PC10 dagger) developed for use in archival tis sue, nuclear proliferating cell nuclear antigen expression was immunoh istochemically measured for the overall tumor (total proliferating cel l nuclear antigen) and for each neoplastic cell type present. In addit ion, the primary tumor was examined for the presence of vascular invas ion and determination of the percentage of tumor composed of embryonal carcinoma. Univariate logistic regression analysis revealed higher to tal (p = 0.0001) and higher embryonal carcinoma proliferating cell nuc lear antigen expression (p = 0.0437) to be statistically significant r isk factors for occult disease, correctly predicting its presence 73% and 61.5% of the time, respectively. More importantly, the presence of vascular invasion and a higher percentage embryonal carcinoma were hi ghly significant risk factors for occult disease and were truly predic tive in 80.4% and 77.2% of the cases, respectively. Multivariate logis tic regression analysis revealed a combination of vascular invasion an d percentage embryonal carcinoma to be the best model to predict occul t disease correctly (85.9%). The addition of total or embryonal carcin oma proliferating cell nuclear antigen expression did not improve the clinical use of the model containing vascular invasion and percentage embryonal carcinoma. Although proliferating cell nuclear antigen expre ssion mirrors the biological behavior of clinical stage I nonseminomat ous germ cell testicular tumor to some degree, assessment of vascular invasion and percentage embryonal carcinoma has greater clinical use.