Quantitation of intratumoral thymidylate synthase expression predicts for disseminated colorectal cancer response and resistance to protracted-infusion fluorouracil and weekly leucovorin.

For this cohort, the intratumoral TS/beta-actin ratio had a statistically significant association with response and survival. This relationship for other 5-FU schedules remains unknown. Confirmation of these data in a larger patient population could lead to determination of therapy for disseminated colorectal cancer based on a specific intratumoral molecular parameter.