This work studied the correlation between EGFR and CHRM1–5 and it was found that all muscarinic receptors were present in BRCA-LumA patients; however, only CHRM3, 4, and 5 in BRCA-Basal and CHRM2, 4, and 5 in BRCA-LumB, indicating different muscarinic therapeutical solutions for these subtypes of breast cancer. Here, CHRM3 is linked to breast cancer.