ERCC1 and XPF expression in human testicular germ cell tumors.

Nucleotide excision repair (NER) is one of the factors influencing the cellular sensitivity to anticancer drugs. In the present study we compared the expression of the NER proteins ERCC1 and XPF in 24 testicular germ cell tumors (TGCT) with the corresponding normal testicular tissue of the same patient. Using immunoblotting, we demonstrated in TGCT a significant increase of ERCC1 expression compared to the normal tissue. There was no significant increase in XPF expression in TCGT. Based on histological characteristics TGCT are subgrouped into seminomas and non-seminomas, the latter being clinically more aggressive. Investigating ERCC1 levels in seminomas we found a slightly increased expression compared to normal tissue, which was, however, not significant. Similarly, no significant difference was observed for XPF levels in seminomas compared to normal testis tissue. In non-seminomas, however, we found a significant increase in the expression of ERCC1 (p<0.017) and XPF (p<0.03) when compared with the corresponding normal tissue. Comparing seminomas with non-seminomas, we observed a significant increase in the expression of ERCC1 (p<0.05) and XPF (p<0.007) in the non-seminomas. Furthermore, a correlation between the expression of ERCC1 and XPF was observed. Our data demonstrate that non-seminomas are characterized by an increased expression of ERCC1 and XPF protein compared to seminomas and the normal testis tissue. The data indicate a possible up-regulation of ERCC1 and XPF during TGCT progression.