The reactive cellular population and expression of blood group substance in human colorectal cancer

The correlation between the expression of blood group substance (BGS) and the host's immune response was studied in 23 samples of human colorectal carcinoma tissue. Several monoclonal antibodies against lymphocyte subsets and histiocytes were used for immunostaining of frozen sections, and MoAbs against BGS (A, B, H) for paraffin sections. In proximal colon cancers (10 cases), the cancer tissues showing expression of BGS revealed a greater increase in cells reactive for OKT11, Leu-7, and Leu-M3 than those with deletion of BGS. However, in distal large bowel cancers (13 cases), there was no significant difference between the cancer tissues without BGS expression and those with BGS re-expression. In all locations of the large bowel, cancer tissue showing expression of incompatible antigen revealed a greater reduction of reactive cells than those with expression of compatible antigen. These results suggest that there are disparities in the host's immune response to proximal colon and distal bowel carcinoma, and that factors other than BGS (A, B, H) might influence the immune response in cases with expression of incompatible antigen.