Production of parathyroid-hormone-related protein by cholesteatoma cells in culture

Abstract Specimens of cholesteatoma were removed at surgery from five patients who had evidence of bone resorption. Parathyroid-hormone-related protein (PTHrP) was detected, by radioimmunoassay, in conditioned media from keratinocyte cultures derived from all five samples. Concentrations of PTHrP in conditioned media from secondary cultures were higher for the cholesteatoma cells than for normal keratinocytes from controls matched for age and sex. Thus, production of PTHrP by cholesteatoma may be a contributory factor in the bone destruction commonly associated with this disorder.