Discussion
cancer, death
MUTANT, CANCER
In this post hoc analysis of the AMATERASU RCT, p53-IHC grades showed a positive association with serum p53-Ab levels. Additionally, p53-Ab levels were significantly higher in patients who were p53-IHC (+) than those who were p53-IHC (−). Previously, mutant p53 protein that accumulated in cancer cells was reported to be immunogenic and to lead to the generation of p53-Ab in vitro.The main findings of this study were that daily supplementation of 2000 IU of vitamin D reduced the risk of relapse or death by 27% compared with placebo in the p53-immunoreactive subgroup, defined by positivity for p53-Ab in serum and p53 protein in more than 99% of cancer cells. Results indicated interactions between vitamin D supplementation and p53-immunoreactive subgroup even after Bonferroni correction. Moreover, results showed a similar risk reduction by shifting the cutoff point of p53-IHC from more than 99% to 10% for sensitivity analysis. As preliminary evidence, we previously reported that vitamin D reduced the risk of relapse or death by 52% compared with the placebo group in the p53-IHC (+) cancer subgroup in a post hoc analysis of the same AMATERASU trial.