NCK1 and breast carcinoma: Nevertheless, some studies provided evidence for non-overlapping functions of Nck1 and Nck2 in certain cell types, including for example an exclusive regulation of actin polymerization in response to platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) treatment by Nck2 in fibroblasts and breast carcinoma cells (MTLn3) [3,4].