MMP2 and gastric neoplasm: also developed a tumor‐targeted and matrix metalloproteinase (MMP)‐2 activatable nanoprobe for high spatial resolution MR and low background fluorescence imaging of gastric tumors and lymph node metastases, in which Gd‐doped CuS NPs were modified with cyclic RGD and MMP‐2 cleavable fluorescent substrates.