CXCL12 and breast carcinoma: This result came first from the observation that GABA B antagonists and agonists and even GABA itself blocked CXCL12-elicited chemotaxis in human breast cancer cells, and that a GABA B antagonist blocked the potentiation by CXCL12 of high threshold Ca+2 channels in Rat dopaminergic neurons (Guyon et al., 2013).