Early tumor screening is pivotal for enhancing tumor treatment efficacy and patient survival rates, yet identifying reliable biomarkers for early detection remains a challenge. Previous studies have explored different isoforms of matrix metalloproteinases (MMPs) in serum for their predictive value in tumor, but their results have been inconsistent. Herein, we introduce a novel fluorescent probe, C9 (N-oxide-8-hydroxyquinoline-5-sulfonic acid), designed to specifically label the pan zinc center activity of MMPs (PZCA-MMPs), which in a sense represents the overall MMPs activity in serum. The rational design of fluorescent probe C9 is based on its ability to bind the zinc ions in the structure of MMPs, facilitated by the oxides on hydroxyl (–OH) and nitro oxide (N→O) groups present in C9, as supported by theoretical calculations such as Gaussian and Schrödinger. Experimental validation confirmed its efficacy for detecting PZCA-MMPs in vitro and for fluorescence imaging of MMPs’ zinc ions in cellular contexts, validated through absolute integrated fluorescence intensity measurements at 510 nm. We also demonstrated through in vitro fluorescent analysis that neither metal ions nor abundant serum proteins such as albumin (BSA) and other metalloproteins interfere with the signal response of C9. Notably, in comparative analysis of serum samples from healthy controls and breast tumor patients, PZCA-MMPs showed a highly discriminatory area under the ROC curve (AUC) of 0.9377, surpassing established tumor biomarkers such as CA125, CA15-3, CA19-9, and CA72-4. In particular, for tumor patients, PZCA-MMPs can effectively distinguish between metastatic and non-metastatic patients (*P<0.05). Therefore, this provides a potential alternative biomarker for tumor screening. Future studies aim to further elucidate the clinical utility of PZCA-MMPs using a broader spectrum of clinical samples.
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