CASR and breast cancer: Furthermore, in MDA-MB-231 and in the MCF-7 breast cancer cell lines, CaSR stimulation was found to enhance the expression of Rab27B, a Rab GTPase that is involved in endosomal trafficking (Zhen and Stenmark, 2015), promoting in this way the secretion of pro-inflammatory cytokines and chemokines such as IL-6, IL-1β, IL-8, IP-10 and RANTES (Zavala-Barrera et al., 2021).