Abnormal Expression of Blood Group–related Antigens in Uterine Endometrial Cancers

The expression of A, B, and H group antigens, Lewis group antigens (Lewis a , Lewis b , Lewis x , and Lewis y ), and Lc4 and nLc4 antigens, the precursor antigens of both groups, was examined immunohistochemically with monoclonal antibodies in 9 normal endometria, 6 endometrial hyperplasias, and 31 endometrial cancers. 1) A, B and/or H antigens were detected in endometrial cancers at an incidence of 51.6%, while no distinct localization of these antigens was observed in normal endometria. H antigen, the precursor of A and B antigens, was particularly frequently detected in endometerial cancers. 2) An increased rate of expression of Lewis group antigens, particularly Lewis b antigen, was observed in endometrial cancers compared with its expression in normal endometria. 3) Lc4 and nLc4 antigens were detected in endometrial cancers at rates of 41.9% and 38.7%, respectively, these expressions being increased compared with those in normal endometria. 4) These results suggest that a highly abnormal expression of blood group–related antigens in endometrial cancers occurs not only at the level of A, B, and H antigens and Lewis group antigens, but also at the level of their precursor Lc4 and nLc4 antigens. 5) Lewis a , Lewis b , and Lc4 antigens, built on the type–1 chain, are more specific to endometrial cancers than their respective positional isomers, Lewis x , Lewis y , and nLc4 antigens, built on the type–2 chain.