Intraoperative quantitative detection of CEA mRNA in the peritoneal lavage of gastric cancer patients with transcription reverse-transcription concerted (TRC) method. A comparative study with real-time quantitative RT-PCR.

BACKGROUND Real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) for detection of carcinoembryonic antigen (CEA) mRNA in the peritoneal lavage of gastric cancer patients is now recognized as a useful method for the prediction of peritoneal recurrence after curative surgery. One problem with this method is that it is time-consuming and difficult to perform an intraoperative diagnosis, which is essential for intraperitoneal adjuvant chemotherapy. PATIENTS AND METHODS In order to overcome these problems, we introduced a transcription-reverse transcription concerted reaction (TRC), which is a non-PCR-based, isothermal mRNA amplification method, as an ultrarapid diagnostic method, and compared its diagnostic power with qRT-PCR for peritoneal washes from 112 gastric cancer patients. RESULTS TRC measurement could be completed within 1.0-1.5 h and showed the same detection sensitivity ranging from 10(2) to 10(6) copies for standard CEA mRNA as qRT-PCR. The CEA mRNA copy number, as determined by TRC, was well correlated with the depth of tumor invasion (pT category), similar to the result obtained using qRT-PCR. With CEA mRNA copy numbers of 100 as a TRC cut-off value, the resultant sensitivity and specificity of TRC (85% and 100%, respectively) were higher than for cytology (62%, 100%) and comparable to qRT-PCR (92%, 100%). CONCLUSION TRC has a diagnostic power almost equivalent to qRT-PCR but with the advantage of ultra-rapid detection. TRC would therefore be available for intraoperative sensitive diagnosis of occult tumor cells in the peritoneal cavity of gastric cancer patients.