The aim of our work was to investigate within the context of a carcinogen-induced tumour, the relative contribution of chemokine-mediated recruitment to the Treg-enrichment process and to determine whether Foxp3+ and Foxp3− CD4+ T cells use the same or different chemokines for migration to tumours, in this case MCA-induced fibrosarcomas. This evidence concerns the gene CD4 and fibrosarcoma.