Establishment of different clonal strains from a human sarcoma of the stomach: tumorigenic heterogeneity in athymic nude mice.

Twenty five clonal strains have been isolated from a single human sarcoma of the stomach. Two different types of clones have been recognized by their morphology and behavior in vitro. Type I clones were characterized by criss-crossed arrays and multilayers with high terminal density. Type II clones grew in a well-organized monolayer with lower saturation density. Although both types of clones exhibited fibroblastic appearance, type I clones showed a more rounded, refractile shape. The cells of this type showed multiple regions of criss-crossed arrays and multilayers throughout the culture vessels. Saturation density of this type of clone was 2- to 3-fold (1.7 to 2.1 X 10(5) cells/sq cm) higher than that of type II clones. Chromosomal analysis revealed that type I clones were human aneuploid ones with modal chromosome numbers ranging from 51 to 61. With the exception of clones 11 and 19, type I clones were able to produce tumors in athymic nude mice when injected s.c. Type II clones exhibited a more flattened and elongated appearance. The cells grew in a well-organized monolayer resembling fingerprint whorls. They showed lower saturation density (0.7 to 0.9 X 10(5) cells/sq cm). Chromosomal examinations revealed the clones to be human aneuploid ones with modal numbers from 47 to 54. Tumor formation was not observed in nude mice given injections of this type of cell. Both types of clones did not bear antigens cross-reacting with the antiserum against mouse spleen cells but had surface antigens which were affected by the antibody against HL-60 cells and complement. These results suggested that this human sarcoma was heterologous and that cells with widely different tumorigenic potential preexisted in the parental cell population.