Targeting a tumor trigger
Every tissue of our body has stem cells that continuously divide to replenish the body with new cells. In previous studies, the research team, headed by Pier Paolo Di Fiore and Salvatore Pece, investigated the role of a protein called Numb in maintaining stem cells in normal mammary gland development in mice. They found that Numb is required for cells to maintain the correct balance between stem cells and differentiated cells in the gland. Numb up-regulates p53, a protein that is known to arrest cell division. When Numb is lost, there is too little p53, resulting in more self-replicating stem cells. This may lead to the formation of tumors. In many human breast cancers, Numb concentration is low and this is associated with a poor prognosis for the patients. In the present study, the researchers take a closer look at the role of Numb in these tumors. They find that tumors lacking Numb have increased numbers of cancer stem cells, thus providing the tumor with a higher potential to s...