CHRM3 and colonic neoplasm: Surmising that M3R-regulated genes important for colon tumor promotion would undergo relatively large changes in expression, for further analysis we arbitrarily set a cut-off at the top 14 down-regulated and top 14 up-regulated genes identified by microarray in tumors from Chrm3-/- compared to WT mice, a total of 28 genes (Figure 4A).