Genetic Lymph Node Staging for Biliary Tract Cancer
Abstracts
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BACKGROUND: Clinical usefulness of genetic diagnosis of lymph node micrometastases has been reported in various cancers. However, either the optimal genetic marker or the clinical significance of genetic staging has not been revealed in biliary tract cancer yet. METHODS: The six candidates for RT-PCR marker, CEA, CK20, PSA, MAGE-1, MAGE-3, and mammaglobin B (MMGB) were examined in 30 biliary tract cancers. We collected 209 lymph nodes from 16 patients with biliary tract cancer. RT-PCR assays using CEA and MMGB as markers were performed and the results were compared with histopathlogical findings. Then, 302 lymph nodes collected from 13 consecutive patients with intrahepatic biliary cancer in the left hepatic lobe were examined by RT-PCR assay using CEA and MMGB genes as genetic markers. RESULTS: Of 30 biliary tract cancer tissues, CEA, CK20, PSA, MAGE-1, MAGE-3, and MMGB was expressed in 20 (67%), 11 (37%), 3 (10%), 5 (17%), 6 (20%), and 25 (83%), respectively. Either CEA or MMGB was expressed in 29 (97%) tumors. In RT-PCR assay for lymph nodes, all of 20 histologically metastasis-positive nodes displayed the RT-PCR product of CEA and/or MMGB gene. Twenty four (13%) of 189 histologically metastasis-negative nodes displayed a RT-PCR product of CEA and/or MMGB gene, suggesting the presence of micrometastasis. In 13 patients with intrahepatic biliary cancer in the left hepatic lobe, genetical lymph node metastasis in pericardiac area of the stomach was found in seven patients (54%). Out of the seven patients with genetic metastasis in the pericardiac area, five patients developed the recurrent disease and three patients died of the disease. No evidence of recurrence has not been found in patients without metastasis in this area. CONCLUSION: We established a sensitive RT-PCR assay with CEA and MMGB genes as genetic markers to detect micrometastases in lymph nodes of biliary tract cancer. Lymph node in pericardiac area of the stomach should be considered to be regional lymph node in biliary cancer in the left hepatic lobe since frequent nodal metastasis in this area was genetically detected. |
