Co-localization of CD63 and MDR1 in clinical samples. Tissue microarrays were immunofluorescently stained for CD63 (Green) and MDR1 (Red), as described in the Materials and Methods section. A) A representative image of breast cancer tissue that was positive for CD63 and MDR1. B) Representative image of breast cancer tissue that was negative for CD63 and MDR1. C, D) Co-localization of CD63 and MDR1 (white arrows) was confirmed. Co-localization of CD63 and MDR1-positive cells appears yellow in the overlay image. The blue color indicates nuclei. A, B) The size bar indicates 100 μm. C, D) The size bar indicates 20 μm.