CLDN2 and breast cancer: Given our previous data supporting Claudin-2 as an important promoter of breast cancer liver metastasis [16, 17], we assessed the effect of Dasatinib treatment on the formation of liver metastases following intra-splenic injection of 2776 liver-aggressive breast cancer cells that expressed endogenous Claudin-2 levels and 2776 cells that had stably reduced Claudin-2 expression (Figure 3A).