CTSK and neoplasm: Both tumour models exhibited the same immunohistochemical labelling pattern: tumour cells never exhibited any significant labelling for M-CSF, Dkk-1, RANKL, IL-6 and cathepsin K. Stromal cells in contact with malignant cells did not express Dkk-1, M-CSF and cathepsin K. At a distance from tumour foci, they also failed to express these markers.