Enhancing effect of bevacizumab in the classic bleomycin, etoposide, cisplatin treatment applied in human testicular germ cell tumors

Purpose: This study aimed to evaluate the therapeutic potential of Bevacizumab, a vascular endothelial growth factor (VEGF) inhibitor, in combination with the standard Bleomycin, Etoposide, and Cisplatin (BEP) regimen for the treatment of testicular germ cell tumors (TGCTs). The primary focus was to investigate its ability to enhance treatment efficacy while reducing cytotoxic side effects. Materials and Methods: The half-maximal inhibitory concentration (IC₅₀) of the BEP regimen was determined in the 1618-K human TGCT cell line and subsequently combined with varying concentrations of Bevacizumab. Cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Expression levels of VEGF, Bax, Bcl-2, and Caspase-3 were analyzed by immunohistochemistry. Results: Bevacizumab significantly reduced cell viability in a dose-dependent manner. Bax expression in Group 2 (2.05 ± 1.04) was significantly lower than in the control group (8.63 ± 2.57;). Caspase-3 expression in Group 2 (0.49 ± 0.08) was markedly decreased compared with the control (5.10 ± 3.82), and a similar reduction was also observed in Group 3. Despite the absence of substantial changes in apoptotic markers, the reduction in cell viability suggests that Bevacizumab may act through alternative mechanisms. Conclusion: By targeting tumor vascularity, Bevacizumab may enhance the therapeutic efficacy of the BEP regimen in TGCT treatment. These findings support the potential role of Bevacizumab as an adjunctive agent in TGCT therapy and highlight the need for further validation through in vivo studies.