ITGA4 and breast cancer: This resulted in a 12-fold decrease in the binding affinity of a chimeric antibody with specificity for the TAG72 antigen (Xiang et al, 1995), a >5-fold lower affinity of a humanised anti-ErB2 antibody for binding to breast cancer cells (Carter et al, 1992), and a complete loss of antigen binding of a humanised anti-alpha 4 integrin antibody (Leger et al, 1997).