metabolic

http://scholar.google.com.sg/scholar?q=colorectal+tumors+responding+to+5-fluorouracil&hl=en&btnG=Search&as_sdt=1%2C5&as_sdtp=on

http://scholar.google.com.sg/scholar?cites=9435048140663863978&as_sdt=2005&sciodt=0,5&hl=en

http://www.springerlink.com/content/u751217228752455/

http://clincancerres.aacrjournals.org/content/9/2/786.short

http://www.nature.com/bjc/journal/v89/n8/abs/6601335a.html