CXCR4 and seminoma: As shown by diminished cell viability, enhanced apoptosis induction, and detection of mitotic catastrophes, we confirmed the cytotoxic efficacy of the CXCR4-NDC in CXCR4<sup>+</sup>-GCT cells (i.e. seminoma and yolk-sac tumor), while non-malignant CXCR4<sup>-</sup>-fibroblasts, remained largely unaffected.