When MCF7 human breast cancer cells with very low endogenous mRNA level of OGR1 (Figure 1A) were transfected with the empty vector (control) or vectors containing OGR1 or GPR4 (a GPCR with the highest homology to OGR1), only those cells expressing OGR1 had significantly suppressed migration (Figure 1B), supporting an OGR1-specific inhibitory effect on cell migration. This evidence concerns the gene GPR4 and breast cancer.