Clear cell carcinoma of the human ovary synthesizes and secretes a transferrin with microheterogeneity of lectin affinity.

Human ovarian clear cell carcinoma cell line (transferrin (Tf)-non-producer), HAC 2, cells were adapted to grow in chemically defined synthetic medium when the cells were cultured with medium containing 10 micrograms/ml of insulin at least for 6 months. They synthesized and secreted constantly the 80 kDa protein immunologically similar to human serum Tf (15 +/- 12 ng/ml/10(7) cells/3 days). By sensitive lectin-affinity electrophoresis followed by antibody-affinity blotting technique, a concanavalin A weakly bound or unbound, lentil lectin, a strongly reactive abnormal band, which was rarely found in human serum Tf, was detectable in the Tf synthesized by HAC 2 cells (HACTf). These findings suggest that the HACTf may act as one of the autocrine growth factors and that this heterogeneity of HACTf for lectin affinity is ascribed to differences in the carbohydrate moiety of the Tf.