5-fluorouracil + mitomycin C + uracil + tegafur

This is a combination chemotherapy regimen consisting of four agents: - **5-fluorouracil (5-FU):** A pyrimidine analog antimetabolite that inhibits thymidylate synthase, disrupting DNA synthesis and leading to cell death in rapidly dividing cells. - **Mitomycin C:** An alkylating agent that crosslinks DNA, inhibiting DNA synthesis and function. - **Tegafur:** A prodrug of 5-FU, metabolized primarily in the liver to release active 5-FU gradually. This allows for oral administration and sustained systemic exposure. - **Uracil:** Included as a biochemical modulator; it competitively inhibits dihydropyrimidine dehydrogenase (DPD), the enzyme responsible for degrading 5-FU, thereby increasing and prolonging systemic levels of active 5-FU. The combination leverages multiple mechanisms to enhance antitumor efficacy. Tegafur/uracil (often known as UFT) is widely used in Japan for various cancers due to its oral bioavailability and ability to maintain therapeutic concentrations of 5-FU[1][4][6]. Mitomycin C adds an additional cytotoxic mechanism via DNA crosslinking. The full four-drug combination has been reported in case studies or clinical settings for advanced gastrointestinal cancers such as gastric cancer[3], though more commonly combinations like UFT plus mitomycin C are described.