Based on these data, TMPRSS4 silencing enhanced TNBC radiosensitivity may be due to increase of apoptotic index following by Bcl2, Bax and caspase3 expression impairment The DNA damage is one of the important effects of ionizing radiation on the cancer cells and the inability of cancer cells to repair that DNA damage characterizes the radiotherapy effectiveness (Alizadeh et al., 2015; Mladenov et al., 2013). Here, BAX is linked to cancer.