ABSTRACT
Purpose:To study the radiosensitising mechanism of topotecan in cell and molecule level on Nasopharyngeal carcinoma.Methods:To detect cell cycle,apoptosis index and the expression s of apoptosis genes such as p53, bcl2, bax by FCM.Results:The proliferation index of RT20Gy +TPT 12.5mg/kg group was decreased, while the apoptosis index was increased, with statistical signifi cance by comparison with TPT and RT group. Meanwhile, the expressions of apoptos is genes, such as p53,bcl-2,bax had no statistic significance between each grou p and the control group. Conclusions:The mechanisms of radiosensitizion might be its act ion on cell cycle,proliferation index and stimulation of apoptosis.However,the i nduction apoptosis might be independent of P53,bcl-2 and bax genes.