title: Murine mammary carcinoma 4T1 induces a leukemoid reaction with splenomegaly: association with tumor-derived growth factors.
abstract: A leukemoid reaction with granulocytosis and splenomegaly has been observed in animals and humans with a variety of tumors. We have employed four color flow cytometry to characterize the leukemoid reaction induced by the transplantable mouse mammary carcinoma 4T1 in female BALB/c mice. Gr-1(+) myeloid cells with the morphology of granulocytes increased in peripheral blood from <15% pre-transplant to nearly 80% of total CD45(+) leukocytes at four weeks post-transplant. Though the granulocyte:lymphocyte ratio increased markedly, the absolute numbers of CD19(+) B lymphocytes, CD4(+) and CD8(+) T lymphocytes, and the CD4/CD8 ratio in peripheral blood did not change significantly. Femurs from tumor-bearing mice showed myeloid hyperplasia of the fatty marrow. There was a notable increase in cells with a Gr-1(dim)/CD11b(bright) immature granulocyte phenotype, and these cells were also found in peripheral blood and spleen. Spleen weights had increased 8.5-fold by four weeks post-tumor transplant, mainly due to granulocytic hyperplasia. Cultured 4T1 tumor cells constitutively expressed mRNA for the myeloid colony-stimulating factors G-CSF and GM-CSF, and IFN-gamma-inducible M-CSF transcripts were also detected. Tumors excised from mice had transcripts for G-CSF and GM-CSF, but only G-CSF protein was found in high levels in serum of tumor-bearing mice. These data demonstrate that 4T1 tumor-bearing mice exhibit a leukemoid reaction that apparently is caused by the production of colony-stimulating factors produced by the tumor. The 4T1 tumor may serve as an excellent model for the study of this reaction.
authors.affiliation: Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, NV 89557, USA.
authors.forename: Sally A
authors.initials: SA
authors.lastname: DuPre'
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Hunter
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000473:pathology; D003115:Colony-Stimulating Factors; D005260:Female; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor / Q000097:blood; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000097:blood; D006098:Granulocytes / Q000473:pathology; D007955:Leukemoid Reaction / Q000209:etiology*; D008214:Lymphocytes / Q000473:pathology; D008325:Mammary Neoplasms, Experimental / Q000150:complications* / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013163:Splenomegaly / Q000209:etiology*
chemical_list: D003115:Colony-Stimulating Factors; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor