Enhancement of ADCC of human peripheral blood mononuclear cells by GM-CSF has been described (Grabstein et al, 1986; Thomassen et al, 1989), and GM-CSF in conjunction with monoclonal antibodies has been used in clinical trials for the treatment of colorectal carcinoma (Mellstedt et al, 1991; Ragnhammar et al, 1992) and neuroblastoma (Yu et al, 1997). Here, CSF2 is linked to colorectal carcinoma.