Exposure of chemoresistant cancer cells to PTX, which may uncouple Gαi from receptor activation by ADP ribosylating Gαi [31], obviously suppressed the transcriptional activity of Gli in K562/A02 cells and KB/VCR cells as revealed by Gli-luciferase reporter assay (Figure 2A), indicating the involvement of Gαi in the Gli activation mediated by Smo in chemoresistant cancer cells. This evidence concerns the gene SMO and cancer.