To explore the relative expression of M1R and M3R in established human colon cancer cells, we selected three commonly used cell lines to examine the relative expression of CHRM1 and CHRM3 mRNA (Figure 2A); HT-29, H508, and HCT116 cells were used in many of our in vitro studies of colon cancer cell function [23,24]. Here, CHRM3 is linked to malignant colon neoplasm.