KLK4 and chronic obstructive pulmonary disease: Examples include capthesins (cancer, atherosclerosis, osteoporosis, Alzheimer’s disease), kallikreins (cancer, hypertension and inflammation), serine proteases (cancer), caspases (neurodegenerative disorders), matrix metalloporinases (MMPs; cancer, bronchiectasis, chronic asthma, cystic fibrosis, chronic obstructive pulmonary disease (COPD), etc.), and disintegrin and metalloproteinase domain protease (ADAM; Alzheimer’s disease) [216].