Thymidylate synthase and dihydropyrimidine dehydrogenase are related to histological effects of 5-fluorouracil and...

Thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and vascular endothelial growth factor (VEGF) are associated with the effect of 5-fluorouracil (5-FU) based adjuvant chemotherapy. However, very few studies have investigated the relationship between these factors and 5-FU neoadjuvant chemotherapy for primary gastric cancer patients. In this study, we studied the correlation between these markers and the histological chemotherapeutic effect in advanced gastric cancer with neoadjuvant chemotherapy.

Sixty-two primary advanced gastric cancer patients were recruited into the study. One cycle of continuous infusion of 5-FU (300 mg/m2/day, 14 days) plus drip infusion of cisplatin (15 mg/m2/day, Day one and Day two) was performed as neoadjuvant chemotherapy. Histological chemotherapeutic responses of the resected specimens were classified into responders and nonresponders. TS, DPD, VEGF expressions both before and after neoadjuvant chemotherapy were examined immunohistochemically.

There was an association between the TS-low group and the responders (p < 0.05); the DPD-low group and the responders in both biopsy and surgical specimens (p < 0.01). A combination of the low-TS and low-DPD group was further associated with responders (p < 0.01). The immunoexpressions of biopsied and surgical specimens were significantly associated with each other.

Neoadjuvant chemotherapy for primary gastric cancer with one cycle of 5-FU and cisplatin was associated with histological findings in patients with low baseline TS and DPD. This dual determination may predict for efficacy of neoadjuvant treatment with these drugs.