Circulating tumor cells (CTCs), circulating tumor extracellular vesicles (exosomes), cell-free circulating tumor DNAs (cDNAs), circulating microRNAs, long noncoding RNAs (lncRNAs), proteins and metabolites, tumor-educated platelets (TEPs), CA 19-9, CA-50, CA-125r, matrix metallopeptidase-9 (MMP-9), Kirsten rat sarcoma viral oncogene homolog (K-ras), tumor protein 53 (p53), and carcinoembryonic antigen (CEA) can be detected by liquid biopsies [27]. Here, MMP9 is linked to neoplasm.