Reproducible metastatic growth of K-562 human myelogenous leukemia cells in nude mice.

A reproducible metastatic growth of K-562 human myelogenous leukemia cells occurred in immunodeficient athymic (nude) mice. Although previous studies have shown that K-562 cells grow as local subcutaneous myelosarcomas which continuously release leukemia cells into the systemic circulation in adult mice, metastases were not observed. However, the subcutaneous "priming" of newborn nude mice resulted in the metastatic proliferation of leukemia cells in the lungs, kidneys, brain, and lymph nodes. Three sc injections of 5 X 10(6) K-562 cells on days 1, 7, and 14 of life produced metastases in 51% of the mice. When the initial series of injections was followed by iv injections on days 35 and 42, the incidence of metastases increased to 67%. Karyotypes demonstrated that the tumor cells retained the same human chromosome markers as those in the human patient and tissue culture. These procedures may provide a model for study of the mechanisms of metastases and for chemotherapeutic and immunotherapeutic trials against metastases of neoplasms of human origin.