Figure 8.

Location of endogenous PGRMC1 in breast cancer tissue. (a) Validation of PGRMC1-specific mouse monoclonal antibody 5G7. Breast cancer tissue was labeled with 5G7 with (left) or without (right) prior incubation of the antibody with recombinant PGRMC1 protein. Preincubation of the 5G7 with Δ43hpr6, the cytoplasmic domain of PGRMC1 protein, which served as the immunogen for 5G7, blocks specific detection of PGRMC1 (red). DAPI is used to detect cell nuclei (blue). Magnification: 63×. (b) Differential expression of PGRMC1 in ER-α-positive and ER-α-negative tumor cells. Depicted are 10 different breast cancer tissue samples (in subpanels i to xii) from a tissue microarray labelled for ERα (green) and PGRMC1 using monoclonal antibody 5G7 (red). (i) An ER-α-positive invasive ductolobular breast cancer (magnification: 10×). (ii) Higher magnification of upper boxed area in subpanel i, showing an ER-α-positive duct. (iii) Higher magnification of lower boxed area of subpanel i, showing an ER-α-negative duct. Subpanels iv to xii show nine different breast cancer tissues; on the right is shown the red signal without the green signal from the same image. Magnification: 20×. (iv) ER-α-positive invasive ductal carcinoma. (v) ER-α-negative invasive lobular breast cancer. (vi) ER-α-positive invasive ductolobular breast cancer. (vii) ER-α-negative invasive ductal carcinoma. (viii) ER-α-positive invasive ductal carcinoma. (ix) ER-α-positive invasive ductal carcinoma. (x) ER-α-positive ductal carcinoma in situ. (xi) ER-α-positive invasive ductal carcinoma. (xii) ER-α-negative invasive ductal breast cancer. The figures indicate that PGRMC1 is differentially expressed in ER-α-positive and ER-α-negative tumor cells. DAPI (blue) is used to detect cell nuclei. (c) Differential expression of PGRMC1 in ER-α-positive invasive ductolobular breast cancer sample with a DCIS (comedo type). (i) The tissue is labeled for ER-α (green) and PGRMC1 using ant-PGRMC1 monoclonal antibody 5G7 (red). PGRMC1 is expressed in areas in which ER-α is not expressed. Magnification: 20×. (ii and iii) Depicted is the area of subpanel i with reduced green (ii) or red signal (iii). (iv) Shown is the negative control for subpanels i to iii, using an unlabeled consecutive section, indicating autofluorescence especially in the necrotic center. (v) the boxed area of subpanel i is enlarged. (vi) Depicted is the same ductal carcinoma in situ in a consecutive section labeled for glucose transporter (GLUT)-1 (green) and PGRMC1 using 5G7 monoclonal antibody (red). (vii) the boxed area of subpanel vi is enlarged. PGRMC1 is expressed in GLUT-1-positive, hypoxic cells in a perinuclear fashion. GLUT-1 protein is localized at the cytoplasmic membrane. This sample was taken from an ER-α-positive invasive ductolobular breast cancer with in situ carcinoma components of comedo-type, and the results depicted were typical for 5/5 comedo type tumors in the stained tissue array. Clinical patient data for the tumors depicted in panels b and c are provided in Additional file 1 (Table S2). DCIS, ductal in situ carcinoma; ER, estrogen receptor; PGMRC, progesterone receptor membrane component.