PTK2 and breast cancer: Secondly, in MDA-MB-231 breast cancer cells, it was shown that cAMP direct elevation reduced leptin-induced cell migration, via both cAMP/PKA- and cAMP-Epac-dependent pathways (Fig. 9 – E), and was related to a down-regulation of ITGB3 and FAK proteins level [31](Fig. 9 – F).