A Nature Communications study identifies Cathepsin L as a shared driver of tumor progression and cancer-associated muscle wasting. Investigators used genetic and pharmacologic inhibition to show Cathepsin L suppression slows tumor growth and preserves skeletal muscle mass in murine cancer models. The work frames Cathepsin L as a single actionable node to treat both tumor burden and cachexia. Authors suggest combined anti‑tumor and anti‑cachexia strategies targeting lysosomal proteases could improve survival and quality of life for oncology patients, and they outline preclinical biomarkers for translational development.