To determine whether ISGylation of p53 could consequently promote its tumour suppressive function, an in vivo tumorigenesis assay was performed by injecting BALB/c nude mice with p53+/+ HCT116 cells stably expressing shNS or shISG15 and p53−/− HCT116 cells stably expressing wild-type p53 and its 2KR mutant. The gene discussed is TP53; the disease is neoplasm.