Figure 1.

Structure of the PC and signaling pathways involving cilia in the human thyroid gland and TC. In normal thyroid gland cells, the PC acts as the sensor and regulator of the outside cell signaling. In TC cells, the PC was absent. Absence of the PC block the signal from outside and neighbors, and disturb the signal pathways inside cells, thus lead to uncontrolled cell cycle process and tumorigenesis.