Fig. 7. FACS analysis of KI67 and DNA content in HT1080-derived cells. Flow cytometry was used to measure KI67 expression and DNA content simultaneously. (A) Representative FACScans of TR9-7 cells. TR9-7 cells were incubated in the presence or absence of tetracycline for 72 hours to induce p53. Cells were fixed and incubated with antibodies to KI67, followed by a secondary antibody labeled with FITC. Cells were also stained with propidium iodide for analysis of DNA content. Cells with 2N or 4N DNA content showing positive staining for KI67 are shown. Controls for each treatment were treated identically, except that the antibody to KI67 was not added. (B) Quantitation of the percentage of cells that are positive for KI67. TR9-7 cells were treated as described in (A). WT and GSE cells were left untreated or exposed to etoposide (10 µM) or adriamycin (345 nM) for 72 hours. KI67 and DNA content were measured as described in (A). The percentage of cells with 2N or 4N DNA content showing positive staining for KI67 is shown. The results represent two independent experiments.