Moreover, Langer et al. synthesized dextran-peptide-methotrexate conjugates for tumor-targeted delivery of chemotherapeutics via the mediation of tumor-associated enzymes, matrix metalloproteinase II and matrix metalloproteinase IX, intending to combine the concepts of polymer-drug conjugate and peptide prodrug in their conjugates and exploit the presence of metalloproteinase in tumor vicinity to release active drug molecules [104]. The gene discussed is MMP2; the disease is neoplasm.