[PyNPase and DPD expression potentially predict response to 5'-DFUR treatment for node-positive breast cancer...

Pyrimidine nucleoside phosphorylase (PyNPase) and dihydropyrimidine dehydrogenase (DPD) activity may be related of the antitumor effect of 5'-deoxy-5-fluorouridine (5'-DFUR). To select patients for adjuvant setting of 5'-DFUR, we assessed PyNPase and DPD activity in 41 primary tumors (PTs) and 227 lymph nodes (LNs) of breast cancer patients. Fifty-one patients were involved in this investigation (mean age 54 +/- 12 years). LN metastasis was positive in 23 cases (node-positive group). Metastatic cancer cells were positive in 65 lymph nodes (In + group). PyNPase and DPD activity were measured by ELISA. PyNPase activity in PTs of the node-positive group was significantly higher than in the node-negative group. PyNPase activity in LNs of In + group was also significantly higher than in the negative metastatic cancer cell group. However, no significant differences were noted between these groups in DPD activity. PyNPase/DPD ratio in LNs of the In + group was marginally higher than in the negative metastatic cancer cell group. These data suggest that 5'-DFUR is preferably sensitive in breast cancer patients with lymph node metastasis.