Angiotensin-Converting Enzyme 2 Gene Expression in Breast Tissue.

Our knowledge about coronavirus disease-2019 (COVID-19) is expanding rapidly. Clinicians are eager for vetted information regarding all aspects of this new illness, and this study demonstrates that the level of ACE2 expression in human breast tissue is higher than that in the lung tissue, a major target tissue affected by SARS-CoV-2 infection. This finding strongly suggests that SARS-CoV-2 infection causes breast pathology.