Circulating sialyl Lewis x , sialyl Lewis a , and sialyl Tn antigens in colorectal cancer patients: multivariate analysis of predictive factors for serum antigen levels

Preoperative serum levels of sialyl Lewis(a) (CA 19-9), sialyl Lewis(x) (SLX), and sialyl Tn (STN) antigens in colorectal cancer patients were examined to establish predictive factors for serum levels of these antigens compared with carcinoembryonic antigen (CEA). A total of 308 patients who underwent resection for a colorectal cancer were divided into low and high antigen groups (higher or lower than a selected diagnostic-based cutoff value). The cutoff values were 37 U/ml for CA19-9, 38 U/ml for SLX, 45 U/ml for STN, and 2.5 ng/ml for CEA. The American Joint Committee on Cancer Classification and Stage grouping was used to classify the tumors. Statistical tests were conducted using univariate and multivariate logistic regression analyses. For CA19-9, 81 patients (26.3%) were assigned to the high antigen group: for SLX, 39 (12.7%); for STN, 33 (10.7%); and for CEA, 133 (43.2%). Multivariate logistic regression analysis revealed that predictive factors associated with high antigen levels were female sex (odds ratio [OR], 1.78 vs male sex), T4 (OR, 3.26 vs T1/T2), and M1 (OR, 3.35 vs M0) for CA19-9; M1 (OR, 6.40 vs M0) for SLX; mucinous carcinoma (OR, 8.45 vs well differentiated adenocarcinoma) and M1 (OR, 8.24 vs M0) for STN; and mucinous carcinoma (OR, 7.21 vs well differentiated adenocarcinoma), T3/T4 (OR, 3.84/4.18, respectively, vs T1/T2), and M1 (OR, 6.39 vs M0) for CEA. In conclusion, high serum levels of CA19-9, SLX, and STN are strongly associated with distant metastasis. In addition, high serum levels of CA19-9 may be an independent predictor for female gender and T4, and high serum levels of STN may be an independent predictor for mucinous carcinoma.