Overexpression of EGFR and c-erbB2 causes enhanced cell migration in human breast cancer cells and NIH3T3 fibroblasts.

Overexpression of EGFR and c-erbB2 frequently occurs in human breast cancers, correlating with poor prognosis. Here we show that overexpression of EGFR and c-erbB2 in cell lines increases cell migration, an important step in metastasis formation. The effect of EGFR on migration is dependent on the addition of EGF to the cells.

Grb2 overexpression in nuclei and cytoplasm of human breast cells: a histochemical and biochemical study of normal and neoplastic mammary tissue specimens.

In 20-30 per cent of human breast cancers, the receptor tyrosine kinases epidermal growth factor receptor (EGFR) and c-erbB2 are overexpressed. This overexpression leads to increased mitogenic signalling and is correlated with poor prognosis. Overexpression of associated adaptor proteins, like Grb2, can also induce upregulation of signalling pathways.

c-Src protein expression is increased in human breast cancer. An immunohistochemical and biochemical analysis.

In human breast cancer, c-Src activity is elevated compared to normal breast tissue. It is not yet known whether this increase in c-Src activity is accompanied by an increase in c-Src protein expression. In this study, c-Src activity and protein expression were determined in a series of human breast cancers and in normal breast tissue, using immune complex kinase assays and immunoblotting.

An enzyme-linked immunosorbent assay for the determination of src-family tyrosine kinase activity in breast cancer.

An enzyme-linked immunosorbent assay is described for the determination of protein tyrosine kinase activity originating from the presence of src-like tyrosine kinases in biological samples. In this assay a peptide derived from p34cdc2, cdc2(6-20)NH2, is coupled to the wells of a maleic anhydride-activated microtiter plate. This particular peptide has been described as an efficient and specific substrate for protein tyrosine kinases belonging to the src family kinases (Cheng et al.

Standardization of an enzyme-linked immunosorbent assay for the determination of protein tyrosine kinase activity.

A procedure for an enzyme-linked immunosorbent assay for the determination of protein tyrosine kinase (PTK) activity from cytosolic and solubilized membrane fractions from breast cancers, is described. The general PTK substrate poly(GluNa, Tyr) 4:1 is coated to the wells of a microtiter plate. After incubation with PTK sample and ATP the amount of phosphorylated tyrosyl residues is quantitated with phosphotyrosine specific antibodies and a secondary peroxidase-labeled antibody.