Making capecitabine targeted therapy for breast cancer: which is the role of thymidine phosphorylase?

Thymidine phosphorylase (TP) expression has been found to be elevated in various solid tumors where it is likely involved in mechanisms that regulate cell proliferation, apoptosis, and angiogenesis. Based on these properties, it is tempting to hypothesize a potential prognostic role of TP, suggesting that a high TP expression could predict a poor outcome. On the other hand, TP expression has been studied for its role in predicting benefit from treatment with fluoropyrimidine-containing chemotherapy. Several studies have been conducted on breast cancer. The current evidence on the value of TP is not mature enough to allow its translation into clinical practice. However, several findings support the potentially predictive role of TP. In this light, TP appears to be a promising marker that can give helpful information to predict the benefit from capecitabine-based chemotherapy in patients with breast cancer.