Signaling pathways such as Wnt/Notch/Sonic hedgehog regulate stem-cell renewal, and genes affected in these pathways are associated with oncogenesis. Our objective is to study the molecular and cellular mechanisms that govern the stem cell regulation and how the perturbation in these mechanisms leads to oncogenesis. In our study, we will select the genes of Wnt/Sonic-hedgehog/ Notch signaling pathways those are involved in stem cell regulation and cancers. The knock out/conditional knock out and transgenic mice in the above mentioned pathways will be studied. This study will elucidate the mechanism that governs stem cell regulation and cancer.