High expression rate of Tn antigen in metastatic lesions of uterine cervical cancers.

The significance of altered expression of MN blood group antigens was examined by studies on the expressions of Thomsen-Friedenreich antigen (T antigen) and Tn antigen in primary and metastatic lesions of 29 human uterine cervical cancers. These antigens were measured by the avidin-biotin-peroxidase (ABC) method with peanut agglutinin (PNA) lectin for T antigen and Vicia villosa agglutinin (VVA) lectin for Tn antigen. Proportion of cancer cells expressing Tn antigen was higher in the metastatic lesions than in the primary tumors in 10 of the 29 cases, less in the metastasis than in the primary tumor in one case, and similar in the primary and metastatic lesions in the other 18 cases. Reaction for Tn antigen was positive in 24 (82.8%) of the 29 metastases, and in 17 (58.5%) of the 29 primary lesions. Thus, the rate of Tn antigen expression was significantly higher in the metastases than in the primary lesions (P < 0.05). On the other hand, there was no significant difference between the immunoreactivities of T antigen in metastases and primary tumors. These findings support our previous suggestion that expression of Tn antigen is closely related to the metastasis to regional lymph nodes and may reflect an important role of this carbohydrate in the process of metastasis of cervical cancer.