TP53 and neoplasm: Moreover, consistent with in vitro findings, the uptake of apigenin by 22Rv1-transplanted nude mice was reported to increase wild-type p53, p53-Ser15 phosphorylation, cytochrome c, and cleaved caspase-3 expression in a dose-dependent manner, and the resulting up- and down-regulation of Bax and Bcl-2 levels, respectively, suggest that the inhibited growth of 22Rv1 tumor xenografts is due to the induction of p53 pathway-mediated apoptosis.