Lectin binding in tissues from hydatidiform mole, invasive mole and choriocarcinoma to concanavalin-A, wheat germ agglutinin and peanut agglutinin

A LIGHT microscopic analysis of lectin receptors in normal placenta and trophoblastic disease was performed utilizing biotinylated Concanavalin-A (Con-A), wheat germ agglutinin (WGA), and peanut agglutinin (PNA), in conjunction with an avidin-biotin peroxidase complex. Hydatidiform mole, invasive mole and choriocarcinoma exhibited increased receptors to Con-A and WGA compared to normal placenta. Increased reactivity to Con-A and WGA was associated merely with increased growth and proliferation of trophoblasts rather than a malignant transformation. Normal placenta, partial and complete mole generally showed moderate to strong binding with PNA after neuraminidase treatment, while invasive mole and choriocarcinoma (11 of 15 cases) generally showed minimal to absent reaction with PNA. Heterogeneity of PNA binding in choriocarcinoma was manifested by the presence of PNA reactivity in the trophoblast membrane in 2 cases wherein no prior neuraminidase treatment was given. This suggests that in some malignant trophoblasts, there is absence of sialic acid in the terminal cell surface carbohydrate groups resulting in the exposure of N-acetylgalactoseamine.