In vitro and in vivo anticancer efficacy of unconjugated humanised anti-CEA monoclonal antibodies

Elevated expression of carcinoembryonic antigen (CEA; CD66e; CEACAM5) has been implicated in various biological aspects of neoplasia. Carcinoembryonic antigen has been shown to be involved in both homophilic and heterophilic binding ( Benchimol et al, 1989 ), suggesting to some that it is an intercellular adhesion molecule involved in cancer invasion, adhesion, and metastasis ( Yoshioka et al, 1998 ). Carcinoembryonic antigen also serves an anti-apoptotic function ( Ordonez et al, 2000 ). Studies have shown that CEA affects the expression of various groups of cancer-related genes, especially cell cycle and apoptotic genes, protecting colonic tumour cells from various apoptotic stimuli, including 5-FU therapy ( Soeth et al, 2001 ).