Fecal RNA detection of cytokeratin 19 and ribosomal protein L19 for colorectal cancer.

Background/aims: We attempted to specifically quantify transcripts of faecal cytokeratin 19 (CK19) and ribosomal protein L19 (RPL19) RNA expression of colorectal cancer and clarify their correlation with clinicopathological parameters and survival in combination.

Methodology: Solid fecal samples were collected and preserved before any treatment. Levels of faecal CK19 and RPL19 mRNA were measured using quantitative real-time PCR. An expression level higher than median value was defined as positive.

Results: Between April 2001 and June 2007, 92 patients were recruited. The levels of both markers increased in a trend as stage. Young patients (< 67 years) were correlated with higher rate of CK19+ (p = 0.001), so were higher stages but with borderline significance (p = 0.051). CK19+ and RPL19+ were highly correlated mutually (p = 0.001). Neither CK19+ (p = 0.12) nor RPL19+ (p = 0.14) alone was a prognostic factor of disease-free interval. However, CK19+/RPL19+ was shown to be with worse prognosis (p = 0.037), but not an independent factor in multivariate analysis with stage.

Conclusions: Both markers were significantly higher in the patients of metastatic disease. The use of two markers will recognize the high risk group better than the single marker usage, though not reaching independent status yet. Multi-target strategy assay is suggested for fecal RNA examination.