KLK4 and cancer: First, proteases are central to cancer hallmarks including neo-angiogenesis, recruitment of immune cells, and enhancement of cellular invasion,52 many akin to the development of adherent VS.13 Second, previous work has implicated MMPs, caspases, and kallikreins in VS patients with poor hearing or those that underwent subtotal resections.18 Third, proteases serve as excellent biomarkers due to their catalytic activity, enabling highly sensitive measurements in complex samples.