Interestingly, most recent studies show that regulators of G protein signaling (RGS) proteins can control cilia assembly or functions to regulate signaling transduction and cell activity.21,22 For example, RGS5 is located in the cilia and can inhibit sonic hedgehog signaling in stem cells.21 RGS18 is highly expressed in the cilia of hair cells, and deletion of RGS18 dramatically reduces cilia numbers.22 Forced overexpression of RGS2 enhances ciliary beat frequency in human airway epithelial cells.23 However, how RGS proteins regulate cilia and oral cancer pathogenesis remains undefined. This evidence concerns the gene RGS18 and lip and oral cavity carcinoma.