Investigation of cell free BIRC5 mRNA as a serum diagnostic and prognostic biomarker for colorectal cancer.

Background: BIRC5 (Survivin), a key member of inhibitor of apoptosis family, has been shown in colorectal cancer (CRC) tumorigenesis and progress. This study investigated the expression levels of cell free BIRC5 mRNA in serum of CRC and assess its diagnostic and prognostic potential.

Methods: Levels of cell free BIRC5 mRNA were detected by reverse transcription quantitative real-time PCR in serum of 92 CRC patients and 60 healthy volunteers.

Results: Cell free BIRC5 mRNA levels were significantly increased in serum of CRC (P < 0.001), and significantly correlated with tumor differentiation (P = 0.035), regional lymph node metastasis (P < 0.001) and TNM stage (P < 0.001). ROC curve demonstrated an optimal cut-off value of 0.128, providing a sensitivity of 84.8% and a specificity of 80.0% for discriminating CRC from controls. The area under the ROC curve for BIRC5 mRNA was significantly larger than that for CEA (0.855 vs. 0.691, P < 0.001). Furthermore, a significantly higher diagnosis capability was showed when combined BIRC5 mRNA and CEA. High serum BIRC5 mRNA expression has a lower OS, compared with low group (36.4% vs. 73.3%, P = 0.022), and was an independent prognostic factor for CRC.

Conclusion: Serum cell free BIRC5 mRNA is a promising non-invasive biomarker for diagnosis and prognosis of CRC.