Abstract

Blood group isoantigens (BGS) A, B and H comprise a group of carbohydrate cell surface markers found not only on the erythrocytes but in wide variety of epithelial cells and body fluid on 80% of the human population. There has been increasing interest in the changes in blood group A, B and H antigen expression in various epithelial malignancies. These changes included deletion of A, B determinants, accumulation of precursor substances, increment or neosynthesis of imcomplete blood group antigens and synthesis of sialylated substances bearing blood group carbohydrate chains. Also these changes have been explained as an evidence of immunologic dedifferentiation analogous to the morphologic dedifferenctiation of anaplasia. isoantigens may be altered in epithelial tissues that show repair and regeneration, metaplastic changes and dysplasia. We studied that the changes of blood group isoantigens A, B and H in 30 cases of adenocarcinoma of the colon, 27 cases of adjacent mucosa and 19 cases of metastatic lymph nodes by immunohistochemical study. In ascending, transverse and rectosigmoid colon, the blood group isoantigens A, B and H are positive in 57.1%, 0% and 57.1% of adenocarcinomas and 100%, 50% and 0% in adjacent mucosae, respectively. In ascending colon,the frequency of the metastasis and recurrences in Blood group isoantigen positive and negative cases are 75% and 66.6% and in rectosigmoid colon, those are 50.5% and 90.0%, respectively. In tumors of the ascending colon, there was no significant correlation between antigen content and frequency of metastasis. However, the cancer of the rectosigmoid colon with bloodgroup isoantigen positive were associated with a lower frequency of metastasis than those without blood group isoantigen. (p=0.045). The data suggests that the immunohistochemical studies of blood group isoantigen may be of value in estimating the clinical behavior of certain colon carcinoma.

• Keywords: Blood group isoantigen A, B and H;