In comparison, BAX and PUMA expression was barely or not increased after UV-C irradiation (Figure 5C), which indicated that death of CLL cells induced by UV-C irradiation was not mediated by increased expression of pro-apoptotic genes and therefore would be p53-independent, although UV-C also induced p53 upregulation. Here, TP53 is linked to B-cell chronic lymphocytic leukemia.