Immunohistochemical Characterization of DU-PAN-2 Expression in Endometrial Adenocarcinomas Associated With CA19-9 Expression

Abstract

We analyzed the expression of DU-PAN-2 (Sialyl-Lewisc) and CA19-9 (Sialyl-Lewisa) immunohistochemically in a total of 133 operated cases of endometrial adenocarcinoma (EMA). These cases were histologically divided into three groups: grade 1 (G1), ≤5% of a nonsquamous or nonmorular solid growth pattern (71 cases); grade 2 (G2), 6–50% of a nonsquamous or nonmorular solid growth pattern (34 cases); and grade 3 (G3), >50% of a nonsquamous or nonmorular growth pattern (28 cases). The immunoreactivity ratios of DU-PAN-2 and CA19-9 were G1: 81.7% (58/71) for DU-PAN-2, 70.4% (50/71) for CA19-9; G2: 76.5% (26/34) for DU-PAN-2, 47.1% (16/34) for CA19-9; G3: 60.7% (17/28) for DU-PAN-2, 32.1% (9/28) for CA19-9. DU-PAN-2 was expressed in 76.0% (19/25) of premenopausal cases and in 83.3% (65/78) of postmenopausal cases, and CA19-9 was expressed in 60.0% (15/25) of premenopausal cases and in 61.5% (48/78) of postmenopausal cases, indicating no significant differences in expression of these antigens between both groups. The difference between immunoreactivity ratios of DU-PAN-2 and CA19-9 tended to increase as EMAs became less differentiated, resulting in the predominance of DU-PAN-2 expression in G3. EMAs positive for DU-PAN-2 exhibited a more favorable clinical outcome than those negative for this antigen. The similar tendency was noted in the survival curves with CA19-9. We concluded that DU-PAN-2 expression was more frequent than that of CA19-9 in EMAs of various grades, with no correlation to menopausal status, and would be more specific for less differentiated EMAs. These antigen expression patterns might be associated with changes in Lewis enzyme activity.