531
The etiology of neurotoxicity in our two patients remains unclear; however, as CAP is rapidly metabolized to 5-FU in patients with normal liver function, it is likely that 5-FU or its active metabolites (fluoro-beta-alanine) were contributing factors.
 ( adverse event: contributing ,  two patients: Subject, two: Subject.Population, neurotoxicity: Effect, 5-FU or its active metabolites (fluoro-beta-alanine): Treatment, 5-FU: Treatment.Drug, fluoro-beta-alanine: Treatment.Drug) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: adverse event,potential therapeutic event, Arguments type: Treatment.Disorder,Treatment.Time_elapsed,Treatment.Dosage,Subject.Race,Treatment.Drug,Treatment.Route,Subject.Disorder,Treatment.Freq,Treatment,Effect,Subject.Population,Treatment.Duration,Combination.Drug,Subject,Subject.Age,Subject.Gender. 
Text: {0} 
Answer:
 ( adverse event: contributing ,  two patients: Subject, two: Subject.Population, neurotoxicity: Effect, 5-FU or its active metabolites (fluoro-beta-alanine): Treatment, 5-FU: Treatment.Drug, fluoro-beta-alanine: Treatment.Drug) 