What does breast cancer 2(3+) mean?

HER2 is an important prognostic indicator of breast cancer and a predictor of the efficacy of anti-HER2 drug therapy. Targeted anti-HER2 drug therapy is indicated for HER2-positive invasive breast cancer. HER2 positive is defined as a positive standard immunohistochemical test 3 or ISH test. If the patient's immunohistochemical test shows HER2 is 3, it can be directly judged as HER2 positive. If the immunohistochemical test HER2 is 2, ISH test positive should be performed again for /confirm/iation. HER2 negative if HER2 is 1 or HER2 is 0 on standard laboratory immunohistochemistry tests.