These differences may well correspond to the tissue type examined, the time in which the analysis was performed (Rnf5−/−  mouse tumor samples were collected 2–3 weeks after tumor inoculation, whereas human tumor samples were obtained at different stages of their development, or following therapy) or exposure of human tumors microenvironmental factors not present in the Rnf5−/− mice. This evidence concerns the gene RNF5 and neoplasm.