DNA damage in clinical radiation therapy studied by microelectrophoresis in single tumour cells. A preliminary report

Aspiration biopsy specimens were taken from malignant tumours--1 Hodgkin's lymphoma, 3 non-Hodgkin lymphomas, 1 squamous cell carcinoma and 1 adenocarcinoma-before and after irradiation. Individual cells were analysed by micro-electrophoresis, a new technique which estimates radiation-induced DNA strand breaks. The cells were embedded in agarose gel; after lysis of the cells in a neutral detergent solution, an electric field (5 V/cm) was applied for five minutes. DNA showed a tendency to migrate, some cell diameters, and was more pronounced in irradiated than in control cells. The DNA migration was evaluated by a microscope photometer which estimated the fluorescence in cells stained with acridine orange. This technique was found to be suitable for human material in vivo as only a few cells are needed and no radioactive prelabelling is necessary.