Difference in prognostic value between sialyl Lewisa and sialyl Lewisx antigens in blood samples obtained from the drainage veins of the colorectal tumors

Subtraction values, (i.e. values obtained by subtracting the serum titer of sialyl Lewisa (CA19-9) and sialyl Lewisx (SLX) antigens in peripheral venous blood from the serum titer of the same antigen in the tumorʹs drainage venous blood) were determined in order to clarify whether or not such values for these specific antigens (d-CA19-9 and d-SLX) are prognostic factors after resection for colorectal cancer. The blood samples were obtained from 144 colorectal cancer patients during surgical excisions of the tumors. Univariate and multivariate analyses revealed that d-SLX level was an independent prognostic factor, separate from stage, while d-CA19-9 level did not have any additional prognostic value. In conclusion, a high d-SLX level is a predictor of poor outcome after surgery.