Rapid detection of CEA mRNA in peritoneal washes using One-Step Nucleic acid Amplification (OSNA) for gastric cancer patients

Background: Carcinoembryonic antigen (CEA) mRNA expression in peritoneal washes from gastric cancer patients has been reported as an indicator for survival or peritoneal recurrence. The whole process of CEA mRNA detection is time- and labor-intensive. We report the potential of One-Step Nucleic acid Amplification (OSNA) as a rapid and simple system for CEA mRNA detection in peritoneal washes.

Methods: A total of 128 peritoneal washes were analyzed by cytological examination including immunocytochemistry. After the cytological examination, the CEA mRNA concentration in the residual cells was measured using the OSNA system. The CEA mRNA concentration in peritoneal washes was compared with the results of the cytological examination.

Results: CEA mRNA at concentrations from 10 to 10(7)copies/μL was detected by the OSNA system within 10 min, and an excellent correlation was observed between the logarithmic CEA mRNA concentration and the detection time (r=0.998). The CEA mRNA cutoff value for distinguishing positive and negative cases through cytological examination was identified as 25 copies/μL. At this cutoff value, the concordance rate with the cytological examination was 93.8%. The overall survival in CEA mRNA-positive versus -negative cases identified using the OSNA system was statistically significant.

Conclusion: This CEA mRNA detection system shows potential for cancer cell detection and for routine use in the clinical laboratory because of its simplicity and rapidity.