Objectives: Carbohydrate antigen 19-9 (CA19-9) is one of the most representative tumor markers in colorectal carcinomas. We studied the immunohistochemical expression of CA19-9 in primary colorectal carcinoma to identify its significance as a prognostic factor.
Methods: The avidin-biotin-peroxidase complex method was used for CA19-9 staining in sections from 149 patients with primary colorectal carcinoma. The data were studied by univariate and multivariate analyses.
Results: 86 tumors (56%) stained positively. The staining pattern was classified into three groups: group I (a stromal type, 22 tumors), group II (an apical and/or cytoplasmic type, 64 tumors), and group III (no staining, 63 tumors). Eight clinicopathologic variables showed a significant relationship with the staining pattern of CA19-9. The 5-yr survival rate of the group I subjects was significantly lower than that of the other two groups. With the multivariate analysis, the staining pattern of CA19-9 proved to be one of the independent prognostic variables.
Conclusions: In addition to conventional prognostic factors, the staining pattern of CA19-9 is considered to be of value in predicting the prognosis of patients with colorectal carcinomas.