Rapid genetic diagnosis with the transcription-reverse transcription concerted reaction system for cancer micrometastasis

Background: Detection of cancer micrometastases is required for improvement of cancer therapy. The aim of this study was to establish a rapid and practical genetic assay to detect micrometastasis in gastric cancer and to assess its clinical significance with respect to prognosis. Methods: A novel RNA amplification system with transcription-reverse transcription concerted reaction (TRC) was introduced for quantitative detection of cancer-specific carcinoembryonic antigen messenger RNA. The sensitivity and quantitative aspects of the assay were assessed with the full-length carcinoembryonic antigen messenger RNA, a gastric cancer cell line (MKN-45), and metastatic lymph nodes obtained from patients with gastric cancer. Peritoneal lavage fluid specimens that were collected from gastric cancer surgery were subjected to the assay, and the clinical significance of the results was examined for prediction of recurrence and survival. Results: The quantification, sensitivity, and reproducibility of the assay with the TRC reaction were equal to those of quantitative reverse transcriptase-polymerase chain reaction with Light-Cycler. The most important advantages of the assay were its simplicity and rapidity. Molecular diagnosis of peritoneal lavage fluid by the TRC reaction significantly correlated with depth of invasion, peritoneal metastasis, clinical stage, overall survival, and peritoneal recurrence-free survival. Conclusions: Molecular diagnosis of peritoneal lavage fluid with the TRC reaction could be a useful prognostic indicator for peritoneal recurrence and survival. Because the TRC reaction is more rapid and simpler than reverse transcriptase-polymerase chain reaction as a format for detecting RNA sequences, it may enhance the genetic diagnosis of cancer micrometastasis and may improve cancer therapy.