In the current study, while no conclusive evidence was obtained that the S-1 treatment resulted in the downstaging of the cancer, it is reasonable to speculate that the CDHP in S-1 was significant, and may have enhanced the antitumor efficacy of 5-FU through the inhibition of the excess DPD produced by the tumor, although, additional studies may be required to confirm this. Here, CDH3 is linked to cancer.