MAPK1 and breast carcinoma: Additionally, overexpression of PLCδ4 in MCF-7 breast carcinoma cell line promotes oncogenic properties through the upregulation of Erb-B2 Receptor Tyrosine Kinase 2 (ErbB2) expression and activation of the ERK pathway [115] which is implicated in cell migration through its regulation of focal adhesion proteins, paxillin and focal adhesion kinase (FAK).