SPUTUM CELLS FROM LUNG-TUMOR PATIENTS CARRY A CELL-SURFACE MARKER NOTFOUND IN NORMAL SPUTUM

Cells were collected from sites of known lung tumours and correspondin g control areas of these lungs. Fluorescent staining demonstrated that the tumour cells and epithelial cells (cytologically these cells appe ared normal) both possessed a receptor for these fluorescent probes. F luorescent labelling of sputum cells from these tumour patients also r esulted in flourescent labelling of these ''cyto- logically normal'' e pithelial cells. No such flourescent epithelial cells were observed in sputum samples collected from control subjects or in cells collected from the control areas of the tumour patients' lungs. We conclude that a cell surface protein receptor is expressed in lung tumour-associate d epithelial cells but is absent from control sputum epithelial cells.