The expression of MDM2 increased more than sham-irradiation, which may be caused by the decrease of p53 induced by feedback regulation of MDM2.

• MDM2蛋白表达增加，高于假照水平，提示p53受到抑制可能不是完全由shRNA引起，升高的MDM2也可能以负反馈调节的形式调控p53的表达。