Long-term in vitro growth of a heterologous mixed Müllerian tumor of the ovary

This paper describes the long-term culture and characterization of a human ovarian heterologous mixed Müllerian tumor, initially acquired from a nude mouse heterotransplant. Microscope examination of the heterotransplants revealed that epithelial and heterologous elements of the original tumor were serially transplanted. After an initial 2- to 4-day lag period, the cells entered a linear growth phase until confluence was reached and the cells passaged. The cells have been in culture for 15-18 months, and passaged approximately 8-10 times. DNA flow cytometry of the cultures revealed the presence of two hyperdiploid cell populations, presumably the epithelial and heterologous portions of the tumor. The cells remain tumorigenic in the nude mouse and form colonies on semisolid medium, attesting to the maintenance of their neoplastic identity following long-term culture. Immunofluorescent labeling for collagen revealed the presence of types I, III, V. The presence of types I, III and V collagen was also confirmed using gel electrophoresis of radiolabeled collagen from these cells. This is consistent with bony tissue, since fibroblasts make types I and III, chondrocytes, type II. In view of the poor prognosis of patients bearing these aggressive tumors, this in vitro tumor cell line could serve as a useful model for the study of this type of carcinoma.