Résumé
Over the last few years, many tumor markers have been proposed to clinicians but only a limited number of them meet the necessary criteria to be useful for either screening, diagnosis, prognosis or follow-up of gastrointestinal (GI) tumors. Both CEA and Ca 19-9 have proven to be clinically useful for the detection of recurrent tumors. AFP remains the most useful marker for the follow-up of hepatocellular carcinoma (HCC). Its interest for the early detection of primary tumor is debated. Recent data suggest that assays based on monoclonal antibodies to AFP could be used for detection HCC in high risk populations. Decarboxy-prothrombin assay may be a complement to the AFP test in this localization. In addition to GI hormones, serotonin and urinary 5HIAA, Neuron Specific Enolase appears to be a valuable marker for the follow-up of neuroendocrine tumors of the GI tract. Only a few of the new tumor-associated antigens detected by monoclonal antibodies, appear to be promising clinical ly e.g. Ca50 TAG-72, PAO. Monoclonal antibodies to tumor-associated markers have also been used with other techniques: Immunohistochemistry: this technique is useful to the pathologist for the diagnosis of undifferentiated tumors by demonstrating the presence of specific antigens on tissue samples. Immunoscintigraphy: it can be useful for the detection of either metastases of recurrences of colorectal cancer by using anti-ACE antibodies labeled with Iodine 131 iodine 123 or indium 111. However immunoscintigraphy is less sensitive than both ultrasonography and CT scan for localizing hepatic metastases. At the present time the best indication of this method remains the diagnosis of pelvic recurrences.Over the last few years, many tumor markers have been proposed to clinicians but only a limited number of them meet the necessary criteria to be useful for either screening, diagnosis, prognosis or follow-up of gastrointestinal (GI) tumors. Both CEA and Ca 19-9 have proven to be clinically useful for the detection of recurrent tumors. AFP remains the most useful marker for the follow-up of hepatocellular carcinoma (HCC). Its interest for the early detection of primary tumor is debated. Recent data suggest that assays based on monoclonal antibodies to AFP could be used for detection HCC in high risk populations. Decarboxy-prothrombin assay may be a complement to the AFP test in this localization. In addition to GI hormones, serotonin and urinary 5HIAA, Neuron Specific Enolase appears to be a valuable marker for the follow-up of neuroendocrine tumors of the GI tract. Only a few of the new tumor-associated antigens detected by monoclonal antibodies, appear to be promising clinical ly e.g. Ca50 TAG-72, PAO. Monoclonal antibodies to tumor-associated markers have also been used with other techniques: Immunohistochemistry: this technique is useful to the pathologist for the diagnosis of undifferentiated tumors by demonstrating the presence of specific antigens on tissue samples. Immunoscintigraphy: it can be useful for the detection of either metastases of recurrences of colorectal cancer by using anti-ACE antibodies labeled with Iodine 131 iodine 123 or indium 111. However immunoscintigraphy is less sensitive than both ultrasonography and CT scan for localizing hepatic metastases. At the present time the best indication of this method remains the diagnosis of pelvic recurrences.