MD Anderson Cancer Center
https://www.mdanderson.org/cancerwise/her2-positive-breast-cancer--what-it-is--diagnosis-and-treatment.h00-159542112.html
HER2 positive breast cancer: What it is, diagnosis and treatment ...
Aug 22, 2022 ... This type of cancer is called “HER2 positive.” Because it grows more quickly, it's more aggressive than other cancers.