Induction of granulocytic hyperplasia, thymic atrophy, and hypercalcemia by a selected subpopulation of a murine mammary adenocarcinoma.

Three tumor cell subpopulation lines derived from a single, spontaneously occurring BALB/cfC3H mammary tumor were evaluated for their ability to cause a leukemoid effect in mice. One of the BALB/cfC3H tumor cell lines (410.4) produced leukocytosis with neutrophilia, hypercalcemia, and thymic atrophy. A second line (66) produced none of these effects. The third line (168) was intermediate in its ability to affect neutrophil counts and splenomegaly but did not produce thymic atrophy or hypercalcemia. These studies demonstrated that the hemopoietic effect of tumor cells derived from a single tumor was variable and that a tumor cell line which caused neutrophilia also induced hypercalcemia and thymic atrophy, the same association that was reported previously in the case of murine CE mammary carcinoma. These observations will be useful in the further investigation of pathophysiology of tumor-induced leukemoid reactions, hypercalcemia, and other paraneoplastic syndromes.