Patent ID: 8512967

Claim:
A method for identifying a breast tumor likely to respond to trastuzumab, comprising: measuring by immunohistochemistry in a tissue sample obtained from the breast tumor: a) expression of epidermal growth factor receptor (EGFR) polypeptide; and b) phosphorylation of extracellular signal-regulated kinase (ERK) polypeptide, wherein phosphorylation of ERK polypeptide is measured using an antibody specific for an epitope comprising a phosphorylated threonine at position 202 of SEQ ID NO: 3, a phosphorylated tyrosine at position 204 of SEQ ID NO: 3, or a combination thereof; and identifying the breast tumor as a breast tumor likely to respond to trastuzumab, if the breast tumor is positive for EGFR polypeptide expression and negative for phosphorylation of ERK polypeptide.