ERBB2 and metastatic neoplasm: In one study, 193 primary breast tumors and 246 metastatic breast tumors were examined by immunohistochemistry and the B7-H4 positive expression rates were as high as 95.4% in primary tumors and 97.6% in metastatic tumors, and the increased expression of B7-H4 correlated with negative progesterone receptor and HER-2/neu status [33].