Examples of receptor conversion in distant metastases of primary breast cancers in the same patient. ERα positive primary tumor (a) with ERα negative liver metastasis that bears ERα expression in hepatocytes (b). ERα negative primary tumor (c) with ERα positive brain metastases (d). PR positive primary tumor (e) with PR negative skin metastasis (f). HER2 positive (3+) primary tumor (g) with HER2 negative liver metastasis (h).