ACE2 and lung carcinoma: The low level and apparent lack of differential expression of the genes encoding components of the ACE2/Ang 1–7/MAS axis in normal lung tissue and lung tumor tissue are surprising in view of the large body of literature suggesting that the ACE2/Ang 1–7/MAS axis plays an important role in lung function [38], susceptibility to the SARS virus [39], and inhibition of angiogenesis in lung cancer [40].