The pre-incubation of the selected RCC cell lines with sCD40L and the enhancer for 24, 48 and 72 h respectively, had no significant effect on cell apoptosis as showed in Figure 1A. On the other hand, CD40-CD40L cross-linking promoted cell proliferation of RCC cells, as demonstrated with CFDA-SE assay by the decrease of CFSE content over time compared to basal condition in RCC cell lines stimulated with sCD40L at different time points (Figure 1B). This evidence concerns the gene CD40 and renal cell carcinoma.