In another study, investigating the functional role of secretory cathepsin C in breast cancer lung metastasis, cathepsin C was reported to activate neutrophil membrane-bound proteinase-3 (PR3), upregulate IL-1β secretion, and activate p38 and nuclear factor (NF)-κB signaling, thus leading to enhanced neutrophil recruitment [49]. The gene discussed is PRTN3; the disease is breast cancer.