The precursor next hydrolyzes to produce active MMP-2, providing a basis for bone degradation;[13,14] Activation of MMP-13: MMP-13 can activate osteoclasts and trigger a cascade reaction with MMP-2, exacerbating bone degradation;[15] Promoting angiogenesis: the expansion and growth of cholesteatoma requires abundant blood supply to provide nutritional conditions for its continuous proliferation. The gene discussed is MMP13; the disease is cholesteatoma.