FISH detection of PTEN and VEGF gene loci in MCF-10.B2 cells during mammary epithelial differentiation and early mammary tumorigenesis. PTEN (red) and VEGF (green)were detected in paraformaldehyde fixed MCF10A.B2 cells grown for 20 days under 3D growth conditions with 10 days of constitutive activation of ErbB2. DAPI (blue) delineates nuclei. A representative acinus structure is shown. The z-series was recorded with a Zeiss LSM 510 META confocal microscope with a 63x 1.4 NA objective lens at zoom level 3. Optical sections imaged totaled approximately 15-20 microns in thickness. See Fig 2 in Meaburn and Misteli, 2008 J Cell Biol 180:39-50.