Lung adenocarcinoma and lung squamous cell carcinoma showed significant up-regulation of 3 KLKs: KLK6 (7-fold and 19-fold), KLK8 (3-fold and 15-fold) and KLK12 (2-fold and 3-fold) and significant down-regulation of KLK11 (6-fold and 5-fold). Here, KLK12 is linked to lung adenocarcinoma.