742 Epithelial cells in human and murine blood and bone marrow

Cytokeratin positive cells are frequently found in the blood (BL) and bone marrow (BM) of patients with epithelial cancers attributed to metastasis. We document here reproducible presence (ECs) normal human murine BL BM. used four different methods: immunofluorescence microscopy (IF), Krt1-14;mTmG transgenic mice, rtPCR, flow cytometry. To this end, we have made several novel interesting findings. First, discovered rare but pan-cytokeratin+ size small lymphocytes smears cytospins untreated Second, that Epithelial Cell Adhesion Molecule (EpCAM+) constituted 0.18% ± 0.0004 (SEM; n=7 biological replicates, 4 experimental replicates), for BM, 3.53%±0.006 n=3 b.r., e.r.) mononuclear cells. In EpCAM+ constitute 0.45% 0.0006 n=2 5.17%± 0.001 e.r.). virtually all were immunoreactive pan-cytokeratin as determined by IF microscopy. Third, using low (8.6 native GFP+ per 106 analyzed (0.085% viable cells), significant numbers (p<0.0005) BM not result randomness. Fourth, rtPCR detected traces cytokeratins 14 15 mouse Further, cytometric analyses disclosed heterogeneity within population when compared CD45 (0.58% BM; 0.13% BL) CD44 (0.13%) lineage markers. conclude from these observations expressing cytokeratin proteins mRNAs reproducibly detectable among These set stage determining functions most curious