By IHC, these cells showed diffuse positivity for GCT markers including OCT3/4 (Fig. 4B), SALL4 (Fig. 4C), CD117 (c-KIT; Fig. 4D) and D2-40, corroborating the diagnosis of metastatic testicular seminoma, while CAM 5.2 (Fig. 4E), CK AE1/AE3, glypican 3 and β-HCG highlighted the syncytiotrophoblastic cells. The gene discussed is KIT; the disease is testicular seminoma.