CEA antigen is used to detect relapses of colorectal cancer, but is also expressed in pancreatic, lung and breast cancers.9 Similarly, levels of cancer antigen 125 may be elevated in ovarian, pancreatic, lung or breast cancer.9 Ascitic fluid analysis is essential for the diagnosis of malignant ascites (Table 2). This evidence concerns the gene MUC16 and colorectal cancer.