HER-2 (also called HER-2/neu, c-erbB2, ERBB2 or neu) is a transmembrane receptor tyrosine kinase, which is a proto-oncogene, i.e. its activation causes malignant transformation and increases the malignant potential (cell proliferation, invasiveness etc.) of the cells. In human cancers HER-2 is activated via gene amplification, which is a genomic mutation where a small fragment at chromosome band 17q12-q21 is multiplied in a cell up to 50-100 folds.HER-2 is over-expressed in 15-25% of primary breast cancers, can also be found in intestinal type gastric and gastroesophageal carcinomas, ovarian carcinomas, high grade endometrial carcinomas and some salivary duct tumors. Low-level copy number increases have been found also in rare cases of lung tumors.Studies have shown that c-erbB-2 positive breast cancer usually correlates with negative staining for estrogen and progesterone receptors; thus a poorer predictive outcome is correlated with positive c-erbB-2 staining.
Synthetic peptide according to the aa1155-1255 (C-terminal) of HER-2 was used as an immunogen.