Significance of CA72.4 in patients with colorectal cancer. Comparison with CEA and CA19.9.

CA72.4 is a new tumor-associated antigen identified by monoclonal antibodies cc49 and B72.3. Serum levels of CA72.4 were measured in patients with benign and malignant diseases. The cut-off used was 4 U/mL. CA72.4 is a highly specific marker since only 3% of 162 patients with benign diseases had elevated levels of antigen. Forty-four percent of 89 patients with colorectal cancer had elevated CA72.4 levels. Compared with CEA and CA19.9, we have found that CEA (75%) is the most sensitive marker (p less than 0.001). The simultaneous use of two or three markers did not further contribute to the evaluation of patients with colorectal cancer.