Aims: Macrophage colony-stimulating factor (M-CSF) binds to colony-stimulating factor-1 receptor (CSF-1R) and stimulates proliferation and differentiation of monocytes, macrophages and their bone marrow progenitors. M-CSF, CSF-1R, the macrophage marker CD68, and the pan T-lymphocyte marker CD3 are increased in many human cancers. Their prognostic importance in primary prostatic carcinoma has not been fully delineated. The aim was to compare the expression of M-CSF, CSF-1R, CD68 and CD3 in metastatic and non-metastatic prostatic cancer.
Methods and results: Digital video analysis of tumour cell areas and tumour stromal areas was performed in 59 cancer specimens: 32 patients with metastases and 27 patients without metastases. Expression of M-CSF and CSF-1R was recorded as 0 (negative immunoreactivity), 1 (weak), 2 (moderate) or 3 (strong reactivity). Macrophages (CD68) and T lymphocytes (CD3) were detected as proportions of moderately or strongly immunoreactive cells. Patients with metastatic primary cancers showed higher expression of M-CSF (P < 0.0001, P = 0.005), CSF-1R (both P < 0.0001) and CD3 (P = 0.007, P < 0.0001) in both tumour cell areas and tumour stromal areas, compared with the non-metastatic cancers.
Conclusion: This study suggests that expression of M-CSF, CSF-1R and CD3 is a significant prognostic factor in primary prostatic cancers by predicting the development of metastases.