A Method for Examining the Entire Contents of a Cell Suspension

Abstract

RECENTLY, considerable interest has been shown in the isolation of tumour cells from the circulating blood of a proportion of patients with malignant disease. Numerous techniques have been described. In most of these a final white-cell concentrate, which contains any malignant cells, has been prepared for microscopy by simple smears^1–5 or embedding in paraffin and serially sectioning^6–8 or filtration through a ‘Millipore’ membrane^9–11. In such preparations one aims at achieving preservation of morphology and accurate quantitation. The latter is clearly not possible with the smear technique; the large number of slides per specimen, the indefinite edges of the smears and the distortion of cells in the tails of the smears are additional unsatisfactory features. The examination of serial sections of the embedded concentrate is satisfactory but quite impracticable for routine use. Filtration through a ‘Millipore’ membrane does allow quantitation, but in my experience the limited staining procedures and distortion of the cells makes accurate identification of the cell type difficult. Furthermore, the membranes are costly.