ERBB2 and breast carcinoma: In addition, since we already demonstrated that p130Cas/ErbB2 association triggers proliferation of breast cancer cells (as demonstrated by soft agar assay in10), a cell proliferation assay was employed to determine EC50 values of 1 and 2 compounds in BT474 (1 EC50 = 52.3 ± 6.38 μM, 2 EC50 = 239.5 ± 25.98 μM) and in SKBR3 (1 EC50 = 69,8 ± 4.44 μM, 2 EC50 = 273.9 ± 27.18 μM) cells as shown in Fig. 6B,C.