Skin Cell Differentiation (image) European Molecular Biology Laboratory Caption In normal skin (left), the stem cells at the base, shown in green, differentiate into skin cells, shown in red. In mice whose skin has neither C/EBP-beta nor C/EBP-beta (middle), this differentiation is blocked: green-labeled stem cells appear in upper layers of skin, and there are no differentiated skin cells (no red staining). This also happens at the initial stages of basal cell carcinomas. In skin where C/EBP-beta is present but has lost its capacity to interact with E2F, a molecule that regulates the cell cycle (right), skin cells start differentiating abnormally, before they have properly exited the stem cell "program" (yellow/orange). This is similar to what is observed in the initial stages of squamous cell carcinomas, a more aggressive and invasive skin tumor. Credit Claus Nerlov/EMBL Usage Restrictions Policy regarding use Press and Picture Releases EMBL press and picture releases including photographs, graphics, movies and videos are copyrighted by EMBL. They may be freely reprinted and distributed for non-commercial use via print, broadcast and electronic media, provided that proper attribution to authors, photographers and designers is made. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.