Figure 2

Known phenotypic changes in mammary epithelium and breast cancer. (a) Overactivation of p21-activated kinase Pak1 in mouse mammary gland induced hyperplasia. While the wild-type (WT) mouse mammary gland has only one single layer of cells (left panel), the mammary gland of the Pak1-TG mice reveals many layers of cells protruding into the lumen of alveoli (right panel). (b) Immunohistochemical detection of Pak1 in normal and breast tumor sections. Left panel, normal section showing weak cytoplasmic Pak1 expression; right panel, tumor section showing an intense cytoplasmic staining compared with the normal section.