Detection of Gastric Cancer Micrometastases in Lymph Nodes by Keratin 19 mRNA with RT-PCR

ABSTRACT

BACKGROUND: In gastric cancer, lymph-node status is the most important discriminant of patient outcome. In spite of its prognostic importance, lymph-node status is usually examined by a routine histological examination using only one hematoxylin and eosin (H-E) section prepared from a representative cut surface of each lymph node. In order to overcome this drawback, new means based on the polymerase chain reaction (PCR) have recently developed to detect micrometastases in lymph nodes. METHODS: Gastric cancer tissues and lymph nodes were obtained from 9 primary gastric adenocarcinoma patients who underwent gastric resection. A total of 80 lymph nodes and 9 gastric cancer tissues were analyzed by both histologic and molecular examination of keratin 19 mRNA. Regional lymph nodes obtained from patients with benign peptic ulcer perforation were used as normal control lymph nodes. RESULTS: 1) Keratin 19 mRNA was expressed in all patients with gastric cancers, but in none of the 10 normal control lymph nodes. 2) Keratin 19 mRNA was detected in all of the 8 lymph nodes which were histologically metastasis-positive. Of the 72 lymph nodes which were histologically metastasis- negative, 67 were found not to express keratin 19 mRNA, but 5 were found to express keratin 19 mRNA. 3) Especially, of the 3 early gastric cancers which were histologically metastasis-negative, one was found not to express keratin 19 mRNA, but two were found to express keratin 19 mRNA. CONCLUSIONS: Keratin 19 reverse transcripture (RT)-PCR a more sensitive method than histological examination for the detection of gastric micrometastases in lymph nodes and may serve as a useful clinical factor in establishing accurate staging for prognosis and in planning optimum management.