KRAS and neoplasm: Metastasis involves additional critical steps – including attachment to vascular endothelium, and extravasation (Fidler, 1997) – and the relationship between primary tumour vascularity and metastasis could derive from oncogene mutations that – as in the case of k-ras or p53 – influence vascular (Rak et al, 1995; Mehta et al, 2001) as well as tumour metastatic (Bartsch et al, 1998; Maehara et al, 2000) phenotype.