Monocyte tissue factor levels in cancer patients

OBJECTIVE: The association between cancer and thromboembolic disease has been known for over a century. Increased tissue factor expression by endothelial cells, monocytes or macrophages is implicated. Thus, monocyte tissue factor measurements may reflect disease presence or progression.

METHODS: Using a 2 stage kinetic chromogenic assay, monocyte tissue factor levels were assessed in normal controls (n=60), patient controls (hernia or cholecystectomy, n=60) and in patients with benign and malignant disease of the bladder (n=73), prostate (n=81), breast (n=83) and colorectum (n=62). This was performed as baseline (resting cells) and after 6 hours incubation with (stimulated) and without (unstimulated) lipopolysaccharide. Each benign disease group was sub-divided into inflammatory and non-inflammatory categories.

RESULTS: The relative operating characteristic curve for the lipopolysaccharide-stimulated monocyte tissue factor assay showed sensitivity and specificity for cancer, the area under the curve being 0.71. The control groups and the benign non-inflammatory groups gave similar results and were pooled for further analysis. Each malignant group showed higher monocyte tissue factor levels than the control groups for baseline (P< 0.05) and lipopolysaccharide-stimulated cells (P< 0.05). All benign inflammatory groups apart from breast, showed increased monocyte tissue factor levels over controls for baseline (P< 0.05) and lipopolysaccharide-stimulated cells (P< 0.05). In all cases there was no significant difference between the malignant and the benign inflammatory groups. Monocyte tissue factor levels were related to tumor grade or stage, patients’ survival time, serum prostate specific antigen and static bone scan images. Levels were also higher in patients with bladder cancer recurrence and in those who subsequently died.

CONCLUSION: Lipopolysaccharide-stimulated monocyte tissue factor assay showed sensitivity and specificity for cancer compared to controls. Monocyte tissue factor levels are raised in malignant groups compared to controls and non-inflammatory diseases but not when compared with inflammatory conditions. Stimulated cells give better discrimination between the groups and may be useful in identifying high risk individuals. Monocyte tissue factor levels were related to tumor progression.