Bioluminescence imaging of fibroblast activation protein-alpha in vivo and human plasma with highly sensitive probe.

Fibroblast activation protein-alpha (FAPα) has emerged as a biomarker of tumor stromal fibroblasts. FAP was overexpressed in stromal fibroblasts of human malignancies and positively correlated with the depth of tumor invasion, lymphatic metastasis, distant metastases, high TNM stage and poor prognosis. However, the circulating FAP levels in the plasma of gastric cancer patients and the relationship between FAP levels and gastric cancer remain unknown.