PACSIN2 and breast cancer: Consistent with primary cell and animal model studies, Rac1 activity was increased in BC cells of patient expressing Cobll1/SH3BP1 but not in patient without any Cobll1/PACSIN2/SH3BP1 expression, suggesting that the Rac1 pathway is only activated by an exclusive activation of both SH3BP1 and Cobll1 in patients with CML (Figure 6F).