Abstract
Accurate differentiation of benign and malignant breast tumors is paramount for establishing schemes of breast cancer treatment and prognosis. Here we report a near-infrared (NIR) fluorescence probe (YF-1) with the overexpressed cathepsin C (CTSC) in metastatic breast tumors as the detecting substrate. This probe allows accurate identification of malignant tumor tissue specimens among tumor tissue specimens with unknown properties in a blind study. Importantly, a series of visible to NIR CTSC-activated fluorescence probes based on the same strategy realize effective identification of malignant tumor tissues, suggesting that CTSC could be the specific identification substrate of malignant breast tumors. Furthermore, a hydrophilic PEG moiety is coupled into YF-1, producing another CTSC-activated NIR probe (YF-2). YF-2 has excellent tumor-targeting capability, enabling the visualization of lung-metastatic breast tumors. The excellent detection accuracy and construction versatility of CTSC probes pave the way for preoperative diagnosis of malignant breast tumors.