Background: Hyperpentaploidy in testicular nonseminomatous germ cell tumors (TNSGCT) has been associated with progression of disease of patients who initially had TNSGCT in Stage I.
Methods: The authors used flow cytometry to investigate the relationship between ploidy and the clinical behavior in TNSGCT, focusing on hypertetraploid values (DNA index, > 2.00).
Results: Patients with TNSGCT containing an aneuploid stemline with a hypertetraploid value more often had higher clinical stage of disease and a higher chance of relapse in advanced stages. The presence of multiple aneuploid stemlines in the tumors was found more frequently in patients who had higher clinical stage disease.
Conclusions: The results suggest that the presence of highly aneuploid or multiple aneuploid stemlines in TNSGCT are associated with a clinically more malignant behavior.