four human head and neck xenograft ( hnx ) tumour lines grown in nude mice and two murine colon carcinomas ( colon 26 and 38 ) were tested for their sensitivity to 5-fluorouracil ( 5-fu ) and its prodrug 5'deoxy-5-fluorouridine ( doxifluridine , 5'd-fur ) .
C0018671
head
C0016360
5-fu