In vitro characteristics of a human mammary carcinoma prior to and after transplantation into nude mice.

Single cells from a patient (B.E., 65 years) have been isolated by collagenase treatment and cultivated in vitro. The human tumour showed predominantly simple undifferentiated and also tubular structures. The 5th in vitro passage of these cells were characterized by growth curves, DNA-distribution patterns and chromosome numbers. Cells of the 5th in vitro passage were i.p. transplanted in nude mice. The characteristics of the 21st passage of ascitic cells and solid tumour material grown in nude mice were compared with cell characteristics of the 5th in vitro passage. Our results demonstrate that malignant cells (ascitic) are best able to proliferate in vitro after transplantation into nude mice. The number of polyploid cells are increased in this cell population. DNA-distribution patterns and chromosome numbers show a good correlation. Biological properties of human neoplastic cells are dependent on environmental factors.