title: [A case of lung cancer resistant to pemetrexed responding to S-1 monotherapy].
abstract: Pemetrexed(PEM)and S-1 are both cytotoxic anti-tumor drugs that target thymidylate synthase(TS). Here, we report a case of lung cancer resistant to PEM, but responsive to S-1 monotherapy. A 50-year-old male with lung cancer(adenocarcinoma, EGFR mutation negative)at Stage III B(T4N2M0)received PEM as third-line chemotherapy. However, metastatic mediastinal lymph nodes were increased in size. A switch to gemcitabine(GEM)resulted in further enlargement of the nodes and elevation of the serum CEA level. Introduction of S-1 monotherapy(120mg/body/day divided into two doses, 4-week administration every 6 weeks, 6 courses)reduced the size of the nodes and serum CEA was normalized. Although S-1 as well as PEM, target TS, the mechanisms in these two drugs that lead to resistance are not the same. Furthermore, S-1 induces dysfunction of RNA through the generation of fluoro-uridine monophosphate(FUMP). We conclude that S-1 can be a drug of choice, even in cases that show resistance to PEM.
authors.affiliation: Dept. of Respiratory Medicine, Tokyo Medical Center, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Oyamada
authors.forename: Arafumi
authors.initials: A
authors.lastname: Maeshima
authors.forename: Ken
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Kato
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy*; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D004338:Drug Combinations; D019008:Drug Resistance, Neoplasm; D005971:Glutamates / Q000627:therapeutic use; D006147:Guanine / Q000031:analogs & derivatives / Q000627:therapeutic use; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010094:Oxonic Acid / Q000627:therapeutic use*; D000068437:Pemetrexed; D005641:Tegafur / Q000627:therapeutic use*; D014057:Tomography, X-Ray Computed
chemical_list: D000964:Antimetabolites, Antineoplastic; D004338:Drug Combinations; D005971:Glutamates; D000068437:Pemetrexed; C079198:S 1 (combination); D005641:Tegafur; D010094:Oxonic Acid; D006147:Guanine