The frequency of metastatic dissemination as well as the densities of hypoxic foci, IL-8 positive foci and vascular hot spots in the primary tumour were determined as a function of time after tumour initiation to investigate whether vascular hot spots developed from hypoxic foci and whether the development of hypoxic foci/vascular hot spots preceded metastatic dissemination. The gene discussed is CXCL8; the disease is neoplasm.