FAS and breast cancer: For example, increased death receptor Fas (CD95) expression in extrinsic apoptosis could be induced by low-LET IR in lymphocytes of C57/B6 mice [313], in rat C6 glioma cells [314], in human p53 wt breast cancer cells (MCF-7) [315], in human nasopharyngeal carcinoma cells [316] and in HeLa cells [317].