CEACAM5 and colorectal carcinoma: With regards to the prognostic value of serum biomarkers in CRC, although some studies have reported that CEA could be used to predict the survival of CRC patients (Tsai et al., 2016), there were also inconsistent results (Song et al., 2018), which suggested that there was no definite evidence that CEA could act as a reliable predictor of the prognosis of CRC.