PURPOSE: To determine if primary testicular germ cell tumors that overexpress p53 tumor suppressor gene protein have p53 gene mutations. MATERIALS AND METHODS: We examined 30 primary testicular tissues from 26 patients representing two groups. Group one consisted of eleven cases (6 nonseminomatous germ cell tumors and 5 seminomas) in which tissue samples for DNA analysis were microdissected from paraffin block regions with elevated immunohistochemical staining for p53 protein. Group two consisted of 19 testis tumor tissues which had been fresh frozen and were chosen to correspond to archival tissue specimens exhibiting elevated levels of p53 protein. The DNA was extracted from these tissues and subjected to exon specific amplification by polymerase chain reaction (PCR) and cold single-strand conformation polymorphism (Cold SSCP) analysis. RESULTS: In these cases with elevated p53 protein, no p53 gene exon 5-8 mutations were detected except 1 seminoma with a codon 140 silent mutation (no protein alteration). CONCLUSIONS: Testicular tumors appear to exhibit elevated levels of wild-type p53 protein, the significance of which is yet to be elucidated.