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.9 Building on the previous study, this study’s results additionally suggest that vitamin D supplementation may be more effective in improving prognosis in patients who are p53-Ab (+) in serum and p53-IHC (+) in cancer tissue compared with patients who are only p53-IHC (+) independent of p53-Ab status. This evidence concerns the gene TP53 and cancer.