TP53 and neuroblastoma: Firstly, the results of immunoblotting assay revealed that NB and SeC in combination markedly increased the expression levels of total and phosphorylated p53 at Ser15 site, and p-Histone H2A.X at Ser 139 site, which indicated the synergistic amplification of DNA damage by NB on SeC (Figure 4A and 4C).