Figure 3.

Primary cilium and cancer. In normal cells, the primary cilium acts as the sensor and regulator of the outside cell signaling. It ensures the completeness of several signal pathways. It determines the advancement of the cell cycle. In cancer cells, the primary cilium was absent. Absence of the primary block the signal from outside and neighbors, and disturb the signal pathways inside cells, thus lead to uncontrolled cell cycle process and tumorigenesis