EPHA2 and renal cell carcinoma: The results of the TUNEL assay demonstrated that the mean apoptotic index of tumor cells was significantly higher in EphA2-knockdown RCC tissues than in the control RCC tissues on day 18 of tumor maintenance in the orthotopic RCC kidney (7.0 ± 2.3% vs. 1.6 ± 0.9%, p = 0.021; Figure 4A).