In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Context: Immunochemical therapy combining cytokines and chemotherapeutic agents is expected to be effective for treating advanced renal cell carcinoma (RCC). We investigated the mechanism underlying the synergism of interferon-alpha (IFN-alpha) and 5-fluorouracil (5-FU) and the effect of p53 status on the synergy of the combined therapy in RCC cell lines.', 'The synergy of IFN-alpha and 5-FU was analyzed by isobolographic analysis in five RCC cell lines. The effect of combined treatment on apoptosis induction was measured by flow cytometric analysis, Hoechst staining, and caspase activity assay; PCNA expression was investigated by Western blotting to examine the effect of combined treatment on the antiproliferative effect.', 'We demonstrated synergy of IFN-alpha and 5-FU in five RCC cell lines with wild-type p53. IFN-alpha suppressed the proliferation of RCC cells via G1 or G2/M cell cycle arrest without inducing apoptosis, whereas 5-FU induced apoptosis in a dosage-dependent manner. IFN-alpha enhanced the apoptosis of RCC cells induced by 5-FU, whereas 5-FU did not increase the antiproliferative effect of IFN-alpha. However, the synergistic inhibition by IFN-alpha and 5-FU was abolished when the cell lines were transfected with p53 dominant-negative vector.\Question: Does synergy of interferon-alpha and 5-fluorouracil in human renal cell carcinoma require p53 activity?
The synergy of IFN-alpha and 5-FU requires p53 activity, suggesting that p53 status may serve as a predictive factor for response to the combination therapy. Because metastatic RCC frequently has p53 mutations, therapy restoring p53 may markedly improve the response rate of immunochemical therapy combining IFN-alpha and 5-FU.