Stankevicins et al. (2013) demonstrated that low-energy X-rays (5 Gy, 30 kV) are able to increase the expression of miR-34a in normal breast cells MCF-10A and p53-wild-type breast cancer cells MCF-7, while its level remained unchanged in p53-mutant breast cancer cells T-47D. Here, TP53 is linked to breast cancer.