(Fry, 1927;Agnantis & Rosen, 1978;Factor et al., 1977;Holland & van Haelst, 1984;Nielsen & Kiaer, 1985;Tavassoli & Norris, 1986) and tumours in other extraskeletal sites (Andreev et al., 1964;Dorney, 1967;Nishiyama et al., 1972; EshunWilson, 1973;Balogh et al., 1985; Berendt et al., 1985). The origin and nature of these cells and their relationship to osteoclasts and macrophage polykaryons is unknown. They are present in the tumour stroma and are generally thought to represent part of the host reponse to the tumour rather than a type of tumour cell. However, their precise function and pathological significance is yet to be determined.In this study, we have examined the ultrastructure and antigenic phenotype of osteoclast-like stromal multinucleate giant cells (OMGCs) in a case of breast carcinoma. We have employed a wide range of monoclonal antibodies of defined specificity in order to clarify the relationship between OMGCs, tumour cells, the osteoclast and other cells of the mononuclear phagocyte system. In addition, we have functionally assessed whether OMGCs behaved like osteoclasts by observing their response to calcitonin and their ability to resorb bone in the presence and absence of known hormonal factors influencing bone resorption. Our findings have implications for macrophage biology and tumour associated osteolysis.
Materials and methodsBovine parathyroid hormone (PTH) (2,500 U mg-1) was provided by Dr J. Zanelli (National Institute for Biological Standards, London, UK) and dissolved (230 IU ml-1) in 1 ml 0.001 % acetic acid in distilled water containing 1 mg ml-I of bovine serum albumin (Sigma, UK) (BSA (Welwyn Garden City, UK) and dissolved in alcohol. Tissue culture medium used throughout was Eagles Minimal Essential Medium (Flow, UK), supplemented with benzyl penicillin 100 IU ml-1 (Glaxo, UK) and streptomycin 100 pg ml-1 (Glaxo) (MEM); this was used alone for cell isolation and supplemented with 10% heat inactivated FCS (Gibco, UK) (MEM/FCS) for subsequent incubations.Blocks of cortical bone were obtained at necropsy from the femoral midshaft of patients who had died without evidence of bone disease. These were cleaned of adherent soft tissues then cut longitudinally into bone slices (5 x 3 x 0.3 mm approx) with a low-speed bone saw using a diamond wheel (Buehler Isomet, IL). The bone slices were ultrasonicated for 15min in sterile distilled water, washed in acetone and ethanol then stored dry at room temperature.Anorganic bone slices were prepared by placing bone slices in 5 ml of hot (55°C) 1,2 ethanediamine (Hydrazine) (Eastman, UK). The solution was changed after one hour and the bone slices then kept in hot hydrazine overnight (Termine et al., 1973). The bone slices were washed several times in alcohol then left overnight in alcohol. They were then washed in distilled water, dried and transferred to a sterile petri dish and kept at room temperature until used.Patient details A 45-year-old woman had noted a lump in the upper outer quadrant of her left breast which had recently increased in s...