VEGFA and renal cell carcinoma: Figure 2b shows that within 24 h the size of the RCC-spheroids expanded sevenfold in CTL conditions (P < 0.001) and 12-fold upon VEGF challenge (P < 0.001), which is consistent with the presence of VEGF receptors on tumour cells.24 TEM, IFN, and SN-38 significantly decreased tumour spheroid expansion, which is in agreement with the anti-tumour effect of these molecules.25–27 In contrast, no significant effect of SUT on RCC spheroids was observed, which is in agreement with previous data showing that SUT did not affect RCC proliferation at concentrations that inhibit RTK signalling.8