title: Dihydrofolate-reductase and thymidylate-synthase in childhood acute lymphoblastic leukemia.
abstract: The expression of thymidylate-synthase (TS) and dihydrofolate-reductase (DHFR) was analysed immunohistochemically in 110 initial and 28 relapsed childhood acute lymphoblastic leukemia (ALL). Relapse-rates were not significantly higher in initial ALL with overexpression of TS- and DHFR than in ALL without overexpression of the proteins. In addition, the disease-free survival was not different for patients with TS or DHFR-negative and TS- or DHFR-positive ALL. No differences were found in the overall survival times of patients with relapsed ALL and with or without expression of TS or DHFR. Of the initial ALL 42% showed TS-overexpression, whereas of the relapsed ALL 64% of the cases were TS-positive (p = 0.03). The corresponding values for DHFR were 20% and 32% (p = 0.18). The results demonstrate clearly that expression of the proteins TS and DHFR has no importance for the resistance of ALL although the proteins increase during treatment.
authors.affiliation: German Cancer Research Center, Heidelberg.
authors.forename: M
authors.initials: M
authors.lastname: Volm
authors.forename: A
authors.initials: A
authors.lastname: Sauerbrey
authors.forename: F
authors.initials: F
authors.lastname: Zintl
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004351:Drug Resistance; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000201:enzymology* / Q000401:mortality; D015996:Survival Rate; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism*; D013940:Thymidylate Synthase / Q000378:metabolism*
chemical_list: D013762:Tetrahydrofolate Dehydrogenase; D013940:Thymidylate Synthase; D008727:Methotrexate