Combined preoperative CEA and CD44v6 improves prognostic value in patients with stage I and stage II colorectal cancer

Combination of biomarkers may improve diagnosis and have better prognostic value than single markers. The purpose of this study was to investigate whether combined CEA and CD44v6 improves prognostic value in stage I and stage II (stage I/II) colorectal cancer (CRC). Preoperative serum CEA level and the expression of CD44v6 in CRC tissues were examined by electrochemiluminescence immunoassay and immunohistochemistry, respectively. The association of CEA and CD44v6 with clinicopathological features and their possible prognostic values was analyzed. The preoperative elevated serum CEA level and positive CD44v6 expression were detected in 30.1 % (52/173) serum samples and 60.5 % (101/167) CRC tissues, respectively. Patients with an elevated-CEA level or a CD44v6-negative tumor had a worse disease-specific survival (DSS) than those with a normal-CEA level or CD44v6-positive tumor (P = 0.024, P = 0.012, respectively). Moreover, CD44v6 expression could be used in discriminating patients from good to poor prognosis in normal-CEA subgroup (P = 0.043), but not in elevated-CEA subgroup (P = 0.563). Multivariate analysis revealed that combined CEA and CD44v6 was an independent prognostic factor for patients with stage I/II CRC (P = 0.023). However, serum CEA level only retained a borderline significance for correlation with a worse DSS (P = 0.059), and CD44v6 expression alone was not an independent prognostic factor for DSS in multivariate analysis (P = 0.123). These results suggested that combined CEA/CD44v6 had better prognostic value than CEA or CD44v6 alone for patients with stage I/II CRC.