Dr. Tsai [Kenneth G. and Elaine A. Langone Fellow] seeks to understand how the signaling pathway directed by the protein Sonic Hedgehog (Shh) regulates cell-cell adhesion molecules required for correct spatial organization of the neuro-epithelium. Abnormal Shh signaling is associated with several types of cancer, and aberrant regulation of cell-cell adhesion could lead to tumor metastasis. His findings may ultimately lead to understanding and prevention of metastasis in Shh-associated cancers.