In addition, in determining the treatment strategy for breast cancer, there is a study comparing the estrogen (ER), progesterone (PR), and HER2 levels in tissues obtained using needle biopsy and surgical resected tissues (n = 916; 94.8%), PR (n = 1170; 86.7%), and HER2 (n = 881; 98.1%), with very low discordance between ER/PR/HER2 test results. Here, ERBB2 is linked to breast cancer.