Biological characterization of a mesothelioma line in the nude mice. II. Some characteristics of cells cultivated in vitro prior to and after transplantation in nude mice.

Ascitic tumor cells from a female patient with a peritoneal carcinomatosis have been cultivated in vitro. The 25th in vitro passage of these cells were characterized by gowth curves. DNA-distribution patterns, chromosome patterns and drug sensitivity. Cells of the 25th in vitro passage were i.p. transplanted in nude mice. The 14th and 18th passage of ascitic cells and the 3rd passage of the solid tumor material grown in nude mice were compared with cells of the 25th in vitro passage. Changes in DNA-distribution patterns, chromosome patterns and drug sensitivity were observed: The G1/0-peak of the ascitic tumor cells (AP 14, AP 18) revealed a shift to the left. This is in coincidence with the chromosome number reduction found. Differences in sensitivity to Methotrexate and 5-Fluorouracil after transplantation in nude mice were observed. The possible reasons of instability of these biological properties are discussed.