The primary cilium is a well-established target in the pathogenesis of numerous 
developmental and chronic disorders, and more recently is attracting interest as 
a structure relevant to cancer. Here we discuss mechanisms by which changes in 
cilia can contribute to the formation and growth of tumors. We emphasize the 
cancer-relevance of cilia-dependent signaling pathways and proteins including 
mTOR, VHL, TSC, WNT, Aurora-A, NEDD9, and Hedgehog, and highlight the emerging 
role of ciliary dysfunction in renal cell carcinoma, medulloblastoma, and breast 
cancer.