Remarkably, the analysis of the current knowledge of the different GPCRs of the RAS molecular system not only confirms that AT1R could be considered a drug target and that its inhibition by losartan and candesartan could be useful in the treatment of BC, but also identifies Mas-related GPCR member D (MRGD) as a druggable protein. This evidence concerns the gene MRGPRD and breast cancer.