However, expression, correlation, and network analyses have revealed increased levels of ACE2 in the lungs of individuals with respiratory illnesses (COPD, acute respiratory distress syndrome), cardiovascular disease, hypertension, diabetes, chronic renal disease, and cancer5,6,17,29–33 and it is well known that individuals with such co-morbidities are susceptible to severe COVID-19 disease, most likely due to increased ACE2 expression, allowing for greater viral invasiveness. Here, ACE2 is linked to chronic obstructive pulmonary disease.