This is a pre-malignant breast tumor grown from breast cancer cells in a 3D matrix that mimics human breast tissue. The blue represents a nucleus, found in each cell present in the breast tumor. The red fluorescence stain is Vimentin, which is a protein that is heavily produced in invasive tumor cells. The one cell on the left has a lot of Vimentin in it, which might signify that this cell will break away from the tumor and metastasize and form more secondary tumors. The other cells (with less red (i.e. Vimentin) might not. This is striking because this image shows that breast tumors are heterogeneous. Not all cells present in a breast tumor express the same amount of Vimentin. The green stain is Rap1Gap, a tumor suppressor protein used by pre-cancerous cells to prevent the tumor from becoming invasive. Other Information: The image is a 3D reconstruction of 25 z-stacks taken of this tumor structure, taken at 40x magnification with the Zeiss LSM 780 fluorescent microscope. Taken at Wayne State University, Detroit, MI.