Figure 1. Matrix metalloproteinases (MMPs), which are secreted by both tumor and stromal cells, are involved in degradation of extracellular matrix. This degradation is key for metastatic and angiogenic processes.

Figure 2. Structural formulas of matrix metalloproteinase inhibitors: (A) hydroxamate, (B) peptide-hydroxamate, (C) tetracycline. The Rx groups are various chemical substituents, and AA represents a peptide substituent.