CHRM3 and cancer: Interestingly, although there is a significant association between the level of M3R/CHRM3 expression in primary tumors and the presence of CRC metastases, M3R/CHRM3 expression within metastases is not increased, suggesting M3R/CHRM3 overexpression is less important and impactful for cancer cell function once CRC cells have metastasized [44].