KLK9

Kallikrein‑related peptidase 9, also known as KLK‑L3, is a secreted serine protease expressed in skin, cervix and head‑neck mucosal tissues. It drives proteolytic processing of local substrates and supports normal physiological status of epithelial tissues.
Altered KLK9 levels are observed in cutaneous carcinoma, cervical cancer, urothelial carcinoma and head‑neck tumors, enabling auxiliary pathological evaluation for tumor specimens. Drug development for KLK9 is limited to pre‑clinical basic research. Candidate inhibitors only obtain partial in‑vitro cellular validation without complete in‑vivo animal efficacy data. No candidates reach clinical trials and no approved drugs target this protein.