Figure 1.

The expression profiles of HERV-K env protein in breast tissue arrays. A, summary of HERV-K env protein expression in arrays of 182 breast tissue samples, including normal breast tissues from healthy patients without cancer (n = 56), benign breast tissues from breast hyperplasia (n = 7), and BC tissues (n = 119). B, panels 1 to 4, representative samples from multiple breast tissue array slides stained with 6H5. The expression of HERV-K env protein was detected in two BC biopsies (panels 1 and 2) but not in normal mammary tissues (panels 3 and 4). C, detection of HERV-K env protein expression in one 48-year-old female diagnosed with infiltrating mammary carcinoma. Positive-staining tumor epithelial cells (brown color indicated with red arrow) were detected in DCIS (panel 1; magnification, ×40), IDC (panel 2), and metastases to the lymph node (panel 4). Positive-staining was greatly reduced (panel 3; black arrows indicate negative staining) in adjacent uninvolved epithelial cells. Red arrow, however, a few tumor cells were positively stained. D, detection of HERV-K env protein expression in one 59-year-old female diagnosed with IDC. All of the panels in this figure have regions of IDC, DCIS, uninvolved epithelial cells, and normal cells. Positive staining (brown color indicated with red arrows) was detected in tumor epithelial cells from DCIS (panel 1; magnification, ×20) and IDC (panels 1 to 4) but not in normal or uninvolved epithelial cells (negative staining indicated with black arrows in panels 2 and 3). More than 91% (31 of 34 cases) of biopsies containing >70% tumor cells had intermediate or strong expression of HERV-K env protein.