Multiparameter evaluation of the expression in situ of normal and tumor-associated antigens in human colorectal carcinoma.

The immunoreactivity of a panel of monoclonal antibodies (MoAb) was studied in a series of patients with colorectal carcinomas to test the association of antigen expression with other parameters such as histopathologic stage, differentiation, and clinical outcome. Low-level binding to normal tissue and high-level binding to malignant tissue were observed with MoAb defining, respectively, a gastrointestinal cancer antigen (GICA), Leb (distal colon only), A, H type 2 antigen, X-like antigen, and the 200-kilodalton (Kd) protein of carcinoembryonic antigen (CEA). The degree of histologic differentiation correlated with the expression of Lea antigen, A, and Y haptens, whereas a progressive loss of these antigens coincided with loss of differentiation. Two undifferentiated carcinomas expressed only two, H type 2 antigen and a highly glycosylated protein of 20-50 Kd, of the 14 antigens investigated. An interesting, but not significant, association between Leb antigen expression and more extensive disease was found: Whereas 71% of Dukes C tumors were positive for Leb, only 48% of patients with Dukes A and B2 tumors showed the presence of Leb antigen. On the other hand, the presence of B72.3-defined antigen is significantly associated with an earlier stage of disease. Chi-square tests to assess the association of antigen positivity with disease recurrence indicated a significant binding association with tumor recurrence over a broad range of percent positive cells for two MoAb defining different determinants of GICA. Similar associations, but over a narrow range of positive cells, were found for H type 2 antigen and the 200-Kd protein of CEA.