VEGFA and rectal cancer: Landriscina et al (1998) also did not find significantly higher serum levels of VEGF-A in mesenteric blood compared with peripheral blood in patients with colorectal cancer. This finding was recently confirmed in patients with rectal cancer (Werther et al, 2001). These observations suggest that serum VEGF-A might be derived from other sources. However, it might be possible that continuous spilling of tumour-derived VEGF in the circulation might lead, especially considering the half-life of VEGF-A of about 30 min (Eppler et al, 2002), to equivalent levels of venous and arterial VEGF-A.