Green et al (2001) developed a mathematical model for antibody-targeted therapy of colorectal cancer. They collected data on the in vivo distribution of antibodies against carcinoembryonic antigen and identified the most useful parameters for determining antibody localisation: the affinity for the antibody, the flow of the antibody through the tumour and the rate of elimination of the antibody from the tumour. The gene discussed is CEACAM5; the disease is neoplasm.