TP53 and breast carcinoma: In particular, limonin demonstrated cytotoxic effects in a p53-dependent signaling network involving the phosphorylations of ERK, p38, and both serine residues (Ser 468 and Ser 536) of NFκB pathways as found in MCF-7 breast cancer cells, but not in p53 mutant MDA-MB-231 cells [15].