CCNB1 and breast cancer: Similarly, genistein has been shown to induce G2/M phase block in BRCA1-impaired human BC MDA-MB-231 and HCC1937 cells by downregulating cyclin B1 levels due to genistein-induced suppression of seven-transmembrane receptor G protein-coupled receptor 30 (GPR30) activation and Akt phosphorylation/activation [200].